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Building a "Baghdad Battery" by IanW on October 31, 2008
Table of Contents
intro: Building a "Baghdad Battery" ...... 2
step 1: Construction Overview an Materials ...... 3
step 2: Making Fe3O4 for the Iron Electrode ...... 3
step 3: Constructing the Electrode Pairs ...... 4
step 4: Containment of Electrochemical Cells an Other Notes ...... 6
step 5: Monitoring Performance of Cells ...... 9
step 6: Performance of this "Baghdad Battery" replica ...... 11
step 7: How this 'replica' differs from other attempts ...... 14
step 8: Interpretation of the Artifacts ...... 17
step 9: History ...... 18
step 10: On other published accounts ...... 19
Related Instructables ...... 21
Advertisements ...... 21
Customized Instructable T-shirts ...... 21
Comments ...... 21
http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ intro: Building a "Baghdad Battery" The intent of this instructable is to provide ideas for experimenting with battery chemistry in general, and to summarize my experience producing a replica of what is often referred to as the Baghdad Battery. In my version of a replica I argue the artifacts have been misinterpreted in replicas previously built by other investigators. The replica I've created yields not only a better performing cell (capable of 5x the capacity), but one that is rechargeable.
This is not a great cell, and our cars and homes will likely never employ the design, but it is curious that ~2000 years ago people may have been experimenting with electricity. What they were using this electricity for is subject to as much speculation as the actual construction of the "battery" (Perhaps it was not a battery, that is for you to decide).
To keep the interest of the reader and focus on the construction aspects of the replica I will try not to write too much about the history and interpretation by others of the artifacts. Several of the sources listed in Step 10 have already done a wonderful job discussing these details.
A few notes: >Several of the listed artifact photos were found on Wikipedia or widely used on the web, so I am assuming there are no copyright infringements.
>Since this is my first instructable, and it has been a while since I've had to explain anything to someone through writing, I welcome all criticism and suggestions for improvement.
>I would like to reference photos and figures inline with the text since I presume it would be easier for the reader to follow, but I am unsure if there is a way to do this through the instructable editor interface and wiki markup (?) - so for now I am just listing relevant images at the bottom of a step. Also, I'm unsure how to apply subscripts in the editor to write chemical formulas, I'd like to include the half cell reactions - otherwise I can take a screenshot and post it as an image.
Image Notes 1. asphalt seal 2. copper sheet cylinder 3. iron rod
http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ step 1: Construction Overview an Materials Based on an assimilation of the various sources listed in step 10 and several trials exercising possible permutations, the cell I settled on as being most likely is a Cu|Fe3O4 electrode pair immersed in KOH 20% that operates as a rechargeable battery - not a single use battery in which the electrodes are disabled by the reaction, as seen with an acid electrolyte. I think urine is just as likely to be the electrolyte, but I have some health problems and a diet that trends toward an acidic urine, so I was unable to test this. Plus my wife would likely take issue with urine sweating out of a porous jar on our kitchen table. Now that I think about it, she wasn't thrilled about the KOH either.
I did not create a true replica, since I could not find a porous jar with the correct geometry. However, jar geometry should not have much effect on the battery performance. Also, a clear vessel - such as the mason jar I used - is helpful for observing the chemistry. If you want a replica that is similar in form to the artifacts, use an unglazed jar with the geometry seen in the photos, and substitute asphalt for the rubber tape I used as a sealant.
Nothing is precise here, so feel free to substitute similar materials. For example, I used bundles of nails before I could find a large iron nail. Just be careful what you use is uncoated iron, many iron objects in the hardware store will be coated with a polymer or zinc (galvanized). Regardless of where you find the metals, ensure your copper and iron have the oxidation layers cleaned off - I used Al2O3 abrasive to clean the copper, and HCL acid for the iron.
Materials:
sheet of copper, it can be found in craft stores -copper pipe found in the hardware store will work too, but the slit seen in the side of the copper tube (in photos) does improve performance, so try to emulate this construction detail (use a saw or mill) piece of iron with an Fe3O4 coating - I used a large iron nail and created my own Fe3O4 coating, see step 2 for details on creating Fe3O4 mason jar or similar non reactive container for holding the electrolyte and electrodes - if you have a porous clay jar, try this instead stranded and solid wire rubber stopper rubber mastic tape, or if more adventurous, try asphalt rubber gloves an alkaline electrolyte - Potassium Hydroxide (KOH), also known as Potash, or an alkaline urine should work. Note: Be careful with retailers of KOH, since there is some paranoia of KOH in certain areas. My first attempt at purchase was a bad experience and waste of time. I believe the first company I contacted was under investigation for supplying methamphetamine manufacture - I'm not quite sure who the owner thought I was. Anyway, stay away from any companies that rhyme with "Spinner Chemical" and are based in Michigan. I won't advertise the company I did have success with, but if you can read the label in one of the photos, my experience was completely painless with this company.
Image Notes Image Notes 1. don't use rebar - I tried - it is not pure iron, despite what the hardware store 1. this vase would have been perfect for a final replica (except it is glazed), but is guy might tell you an heirloom in my wife's Japanese family, an I would probably get in a lot of 2. rubber mastic, the duct tape of battery cell construction, wonderful stuff trouble if I used it, she caught me inspecting it 3. stranded an solid wire 4. iron nails, I used the large one to the left, but several of the small ones will work too - the bunch to the far right has a light coating of rust, but not enough to create a good layer of Fe3O4 5. wire strippers
step 2: Making Fe3O4 for the Iron Electrode If your iron is already coated with Fe3O4 ('black rust'), you can skip this step. In the photos below, I show bailing wire, one possible option that comes coated with Fe3O4 and can be found in most hardware stores.
The best option is to heat the iron until orange (temperature of decalescence 475 F to 525 F), either in a forge or with a torch, it will oxidise and leave behind Fe3O4.
If you live near an ocean, leaving iron in seawater for an extended period should create a coating of Fe3O4. Or, you might scavenge for some Fe3O4 coated iron near the shorelines - I found some last time I was near the ocean.
Since I am not near an ocean at the moment, don't know any blacksmiths, and wanted to speed up the process, I used the following recipe:
First you will need to create Fe2O3 (red rust). If your iron already has a good coating of red rust, you may skip this part. If you need to make your own red rust, it is a little trickier since you will need to handle a few chemicals, but not bad. My recipe is not optimal, if you have Nitric acid and washing soda you can do better, but neither of these chemicals can be easily found at a hardware store - so, for most people, this recipe should be easier to implement. Near the concrete section of the hardware store, you will likely find something labeled as 'Muriatic Acid' - it is actually 30% HCL. Use your rubber gloves when handling any chemicals. Dip your iron nail in a mason jar of this acid and you will be left with a clean piece of iron ready to be oxidized. Now, pour another jar full of household Clorox bleach (or generic) and dip the cleaned iron into this solution. Allow the iron to dry in a glass dish - and you should have a nice coat of Fe2O3 (red rust). Now that we have a good coat of Fe2O3, we will convert this to Fe3O4. The Fe3O4 will appear as a black coating over the iron, where the red rust was formerly. Heat a pot of water on the stove until it is boiling and place the red rust coated piece of iron you created in the boiling water, after a few minutes it should turn http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ black, now you have Fe3O4.
Image Notes Image Notes 1. a helical electrode I experimented with by wrapping around a chopstick 1. some different experiments with generating Fe2O3, the precursor to Fe3O4, 2. this can be found in most hardware stores labeled as bailing wire or rebar tie boil any of the red colored rust objects for a few minutes an you will have a wire - it is actually iron wire with an Fe3O4 coating applied - notice the black to nice coat of Fe3O4 blue coloring of the wire - this serves to inhibit corrosion on the wire from Fe2O3 attack - if you do not want to make your own Fe3O4 from my recipe, this should serve as a suitable surrogate
step 3: Constructing the Electrode Pairs When testing most cells, just a wrap of rubber tape around the two electrodes is all that is needed, but since this cell is based on a set of artifacts, we want to emulate the dimensions and geometries as closely as possible. Instead of asphalt for the sealant - seen in the artifacts - I used rubber tape. I tried asphalt, but it is messy to work with and clean up, and you have to wait for it to set - when working with several cells at once, it becomes a headache.
The photos should be more explanatory, but roughly:
Drill a hole in the mason jar lid and slide the Fe3O4 coated iron nail through it Drill a hole in the rubber stopper so the Fe3O4 coated iron nail can fit snugly through it with the head of the nail protruding an inch or so from the top - you may want to put a single wrap of rubber tape around the upper exposed portion of where the nail interfaces with the stopper to seal it Form a piece of copper sheet into a cylinder around the rubber stopper so there is a slight opening (as seen in photos) still visible along the side, now wrap the top portion with rubber tape and attach the stranded wire to the side of the copper and then wrap again to seal the copper against the stopper, also put a single wrap of tape at the bottom to help hold the slotted cylindrical form now, slide the wire through the hole drilled in the jar lid and put a wrap of rubber tape to secure the wire to the nail at the point where you would like to interface with the mason jar lid, force the lid down on to this wrap of rubber tape and you should have a tight seal - it should look like photo 1 now, fill your mason jar with 20% KOH or other alkaline electrolyte and place the mason jar lid assembly you just created into the solution and seal the jar - it should look like photo 3
If you just want to evaluate the chemistry and don't need a full scale replica of the electrodes, use reduced dimensions and one of the simpler construction options I outline in the next step. Instead of a slotted copper cylinder and a large nail suspended down the center, the electrodes can be simplified to a strip of copper and iron.
Image Notes 1. stranded wire attached to copper cylinder with rubber tape 2. small opening as seen in artifacts, note the copper sheet has all oxides removed by using an abrasive - it should be shiny 3. I did not include a copper disc as seen in the artifacts, primarily to simplify construction since I was making several cells - iron rod an copper sheet are both isolated here with a few wraps of rubber mastic
http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ 4. stranded wire taped to nail an fed through lid 5. mason jar lid
Image Notes 1. In a discharged cell with the iron rod as the anode, or a cell with the iron rod as the cathode (can be charged or discharged), the electrolyte is clear when using an alkaline electrolyte an the metals stay protected - the mason jar is not accurate relative to the artifacts, but has the benefit of allowing one to observe the electrolyte chemistry 2. stranded wire provides a connection to the copper, granted this is not historically accurate, but is the only way I know to create discharge curves for the cell 3. Large iron nail with a coating of Fe3O4 4. small opening down the center of the copper sheet, as seen in the artifacts, I tried standard plumbing copper pipe without the opening, but this aspect of the geometry seems to improve the cell
Image Notes 1. some earlier cells, what you can't see in the previous photo is that I isolated http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ the iron rod from the copper cylinder using a rubber stopper 2. notice the different states of iron - from left to right - plain iron, Fe3O4, an Fe2O3 - for our final cell we are only interested in the middle one containing Fe3O4 - this photo was taken when I was still evaluating different cells 3. mason jars consume a lot of electrolyte, so when running many trials, an durability is less of a concern, non lubricated condoms work well - even better is to just decrease the dimensions of the electrodes, the chemistry stays the same 4. note, the main difference between these cells an the previous photo is the lack of a slit along the side of the copper cylinder, this helps, so try to have an opening in your copper
step 4: Containment of Electrochemical Cells an Other Notes Although we are primarily concerned with the Baghdad battery in the instructable, this step addresses the containment and construction of any electrochemical cell. I've not arrived at a 'best' cell construction method for quickly evaluating different chemistries, but to provide ideas, I listed photos of various permutations I have attempted - including some earlier versions of my Baghdad cell replica.
I only selected a mason jar as my container because I needed to fit the electrode dimensions of a Baghdad battery. To save time and materials, use much smaller containers and electrode dimensions when evaluating other cells.
Find any sturdy non reactive sealed container that allows for external electrical contact with the electrodes, and if you will be pushing the cell hard, a means to vent any gases that might accumulate (this does not apply to the Baghdad cell).
Materials I have found useful when constructing cells (generally, just use what you have on hand): rubber tape (my new duct tape), rubber stoppers, spice jars, condoms, mason jars, film cannisters, toothbrush holders (also work well for simple voltaic piles), stranded wire to ensure good contact with the electrode surface, emery board or plumber's sand cloth for cleaning metals, liquid tape
One of my current projects is to build a battery monitoring chamber that can run several experiments in parallel and monitor temperature, gas pressures in the cells, etc.. The cells I've constructed for this project are small jars (roughly the size of spice jars) with rubber stoppers that have two slits in them to seal the electrodes, a tube to monitor pressure, and a thermowell contact for temperature - perhaps I'll turn that into an Instructable too.
To Experiment with other chemistries: As you've likely realized, there is not much to experimenting with electrochemistry, place two dissimilar metals in a jar with some fluid. This table should give some ideas when considering different cell potentials.
To learn about batteries in general, the web is fertile ground. I've also found this book to be very helpful (and affordable relative to other battery books). This book is another well regarded alternative, and I highly recommend it if you want a more comprehensive understanding of batteries. I wasted considerable time in some of my experiments by not purchasing it sooner - it contains lots of data on many different chemistries. It will run ~$100 new, but I'm told it can be found for ~$20 used.
Image Notes 1. the full replica Baghdad cell has large dimensions, so spice jars will not work for this, but for all the other cell chemistries I experiment with these are perfect, use a rubber stopper cut in half for the top
http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ Image Notes 1. rubber gloves should be used when handling less sturdy cells 2. condoms are very helpful reaction chambers
Image Notes Image Notes 1. condom as the cap on a spice jar, I prefer rubber stoppers now 1. condom attached to a rubber stopper 2. I used silicone tape here instead of rubber mastic, which works well too, but 2. mason jars are very helpful an cheap to contain cells, chemicals, etc. rubber mastic is cheaper 3. clear vessels are nice not only for observing color changes in electrolyte, but also viewing gas formation - this is actually a different chemistry I was playing with (you'll notice no copper here)
http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ Image Notes Image Notes 1. before I found large iron nails, I used bundles of nails woven with stranded 1. how the stranded wire was attached to the copper cylinder wire and held together with rubber tape - stranded wire seems to work better than solid wire
Image Notes Image Notes 1. rubber cement an liquid electrical tape can also be helpful 1. an almost completed cell - I became better at Fe3O4 coatings later, but the 2. several electrode pairs attached to mason jar tops ready to be immersed in one on these nails is not too bad electrolyte
Image Notes Image Notes 1. several cells ready to go 1. this is a voltaic pile setup I was testing - the thick paper is dipped in 2. liquid electrical tape electrolyte (salt water, etc.) and placed between the metals - I modified an old toothbrush holder to contain it 2. not related, but this fabric is replica hemp sail cloth from the 1700's an is wonderfully durable stuff, I plan to make some clothes out of it an use it for some composite structural forms I'm interested in http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ Image Notes 1. nicely isolated voltaic pile
step 5: Monitoring Performance of Cells If you want to minimize complexity, use only an analog voltmeter and ammeter (0-100mA) and observe the values during charge/discharge - ignore most of the discussion below.
To produce charge and discharge curves for your cells you can either log by hand the readings on your meter, or invest in a DAQ or microcontroller to automate data logging. A spreadsheet or similar application is helpful for plotting data. I am rather fond of the Labjack products (seen in some of my photos) - I used their DAQ+software and opamp. DAQFactory is the software that comes with Labjack's measurement devices and it's a good alternative to Labview. Although I am using the scaled down version of DAQFactory that ships with Labjack's products, it can be upgraded to enable some very sophisticated process control applications, but at a fraction of Labview's cost. The Arduino (Atmega) and Parallax Propeller microcontrollers are good choices too, but will require additional setup time - I am using them for other projects where cost is more of a concern. Labjack + DAQFactory is nice for speed of setup, plus they have a great support staff, but so does Parallax, and arduino has a huge volunteer support community.
Besides a measuring device, consider:
Your measuring device may already have high input impedance (>100Mohm), but if not, use an operational amplifier (opamp), otherwise cells with high internal resistance (such as the Baghdad Battery chemistry) will create problems in your measurements. Opamp's are also helpful to amplify the voltage drop across the current shunt resistor, which is low. Opamps allow differential measurements too, so it is easier to read the voltage drop across the shunt resistor. If not using an ammeter, a small resistor provides a voltage drop for calculating current - ideally around 1 ohm (for the voltage/current of the Baghdad cell) although mine was 0.33 ohm. Using ohm's law simply measure the voltage drop across the resistor (dV) and solve for current I=dV/R, in my case R=0.33 ohm, Watts are calculated as P=I*V A small resistor or other device to act as a load, I used a 330 ohm resistor for the Baghdad battery, which seemed to be an appropriate load for the cell. The resistor value will differ depending on the battery. A terminal block for wiring connections - I find the European style blocks (shown in the photos) easier to use, but stick to the 20A rated blocks since the larger block size is easier to work with and only costs a few cents more To charge the battery, a constant voltage source such as another battery (e.g. earth battery) or in my case a digital to analog converter (DAC) on the DAQ works fine for the Baghdad Battery chemistry, but keep in mind that to properly charge some cell chemistries you will need a constant current source or a mix of both at different time intervals. I generally charged at 1.5 V and limited current to 20 mA - again, similar to what an Earth Battery might provide.
If you are just getting started in electronics and some of the terminology seems obscure, I highly recommend Getting Started in Electronics by Forrest Mims.
Image Notes 1. the DAQ I used - Labjack produces good durable instruments, an comes with LabView like software for viewing traces in real time - but again 2 analog meters will work just as well 2. a very nice programmable operational amplifier that Labjack sells - the EI- http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ 1040 3. another operational amplifier sold by Labjack the LJTIA 4. 0.33 ohm resistor for current measurement 5. 330 ohm load resistor 6. a bitscope oscilloscope, not needed for this experiement 7. this is from another experiment, an you can ignore it, it's part of a circuit that controls a magnetic induction cooktop, perhaps I'll post this in a future instructable since I think it is rather cool 8. to battery anode 9. to battery cathode 10. DAC output on the labjack for charging
Image Notes 1. european style terminal blocks, use the larger versions like this (~20A +), not the smaller versions as to the right (~5A to 15A) 2. nothing beats an analog meter when keeping things simple to troubleshoot a problem - you could use only this an a analog voltage meter to test your cells, just plot the values on a sheet of paper
http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ Image Notes 1. simple cartoon drawing of the circuit shown in the previous photo - I could use proper schematic symbols, but hopefully this communicates just as well - the idea is to show charge/discharge circuits with an analog meter setup OR connection to a DAQ in a single diagram - but maybe I should split this into separate diagrams and use proper schematic symbols
step 6: Performance of this "Baghdad Battery" replica Alright, now that you have your cell built and some means of monitoring voltage and current of the cell, you will want to generate some charge and discharge curves to characterize the cell.
The photos below should tell most of the story, but in summary:
charge at 1.1 to 1.5 V and a few milliamps of current discharge with a 330 ohm load repeat 1-2 times if you like, your cell should be providing about 7 mA-h of capacity. Then let sit for 3 days and you will see the 5x increase in capacity I note below
One very relevant aspect of this chemistry that I almost overlooked, and you will want to emulate: If you let the cell sit for 3 days after an initial charge/discharge cycle you end up with a rechargeable battery that has 5x the capacity - quite a remarkable increase in capacity. So, when I first charged/discharged the cell I thought I had created a replica roughly equivalent to the acid chemistries previously attempted, except with the added benefit of it now being rechargeable. After a 3 day rest though, I had a cell with 5x the capacity of the acid chemistries - my cells now averaged 33 mA-h capacity on a single charge when made according to the dimensions of the artifacts.
This cell likes to take a charge slowly and give it up slowly - it will take three days to discharge with the 330 ohm load, and 1-2 days to charge, I actually never fully charged or discharged the cell since I did not have the patience, and have several other experiments that are in neglect at the moment. The cell seems ideally suited to take a charge from the voltage/current characteristics of telluric currents present in the Earth, or earth battery as some have labeled it. I tested other voltages and currents and they do not seem to work as well. The slow release of current seen in this cell would likely work well to run a homopolar motor but since I have not created a well enough balanced piece of copper or bronze wire yet, I have been unable to fully test this theory. Also, if you attempt to discharge the cell too rapidly (too large of a load) it seems to ruin the cell.
One additional curiosity of the alkaline cell chemistry is that either the Fe or Cu can serve as the anode, although with Fe as the anode it is a better cell. With an Fe anode the electrolyte turns blue upon charge (indicative of Cu ions), and becomes clear on discharge. With Cu as the anode the solution is clear on charge and discharge and the metals actually appear polished.
It should be noted that all of my experiments (and cell performance curves) were done without careful attention to ambient temperature, usually around 55-65 deg. F. We keep our house relatively cool and try to minimize furnace use. Temperature is the most important environmental factor when evaluating electrochemistry, and 80-90 deg. F would likely produce better results, and provide a more accurate recreation of the 'Baghdad Battery' since temperatures were likely much warmer in Mesopotamia. I http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ tested the temperature dependence of the chemistry by allowing a minor ~5 deg rise in temperature and observed a 10% increase in rate of charge current and release of the current on discharge. The increase in charge/discharge rate is a function of what is commonly called internal resistance. Most battery chemistries have a lower internal resistance as temperature increases. As most batteries are cycled, their internal resistance will increase with time - in addition to self discharge rate, and a decline in capacity. I am developing a reaction chamber to control environmental parameters and further automate my other electrochemistry experiments - this will allow a more precise characterization, but the results I've presented will have to suffice for now.
Image Notes Image Notes 1. the color change seen when charging a cell that uses the iron rod as the anode 1. 'blue glass' used as a color comparison with the electrolyte, although this 2. alligator clips work well for attaching conductors to the cell blue is not copper, but cobalt 3. I would place the cells in a separate dish since this protects from any spillage - 2. the color of a charged cell - lots of copper ions also, although the stranded wire is nice for making good contact with the copper, 3. a partially discharged cell - fewer copper ions through capillary action, the KOH will traverse the wire after several days of use 4. no iron rod here, this was before I could find one an was using bundles of an deposit concentrated KOH crystals - be careful nails taped together
Image Notes Image Notes 1. this is a plot of the charge cycle for the cell 1. This is the first part of the discharge curve - note this cell was charged an http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ 2. this is the voltage differential across the resistor used to measure current, then discharged an then allowed to sit for 3 days, which greatly improved the you'll see this in all my plots, although it is not needed, I did it as a sanity check cell - 5x increase in capacity, quite amazing to me, although I list 33 ma-h it is when I was debugging my setup,but never removed the trace, I still like to see it actually a few ma higher in some of my trials since I was experimenting with different resistors the whole time - for the 2. a lot of current is liberated in the first 2 hours of discharge an then tapers off voltage/current of this cell 1ohm might make sense if testing any other cell, but to 0.6 mA for several days of discharge - if running a homopolar motor, one the most I could get away with was 0.33 ohm without causing problems with the could imagine this as the jump start to get the motor spinning quickly an then a baghdad cell stream of maintenance current to keep it spinning 3. the cell's ability to take current is tapering off here, but it will continue at this 3. continued on the next plot, an runs for several days slope for several days if allowed to run - I never fully charged any of my cells due to time constraints - so I've actually not characterized a fully charged cell 4. apologies for the negative values on the axes, remnants from another experiment
Image Notes Image Notes 1. this curve is actually from an earlier cell, but is the curve geometry one would 1. this discharge curve plot shows the cell performance before being allowed to see from the previous photo if allowed to run - the problem is that my DAQ sit for three days, an then recharged - it has 1/5 the capacity or around 0.007 software (the free version of DAQ Factory that ships with Labjack) is limited to 3 A-h days of measurements at the sampling rate I chose (1Hz) - so you'll notice the first part of this curve is missing - - I'm in the process of setting up a dedicated battery test bench with a microcontroller that will write to an SD card to free up my computer, an with all the measurements, it will be better to simply calculate the area under the curve to approximate A-h, I'm averaging by eye at the moment 2. sorry for the dual axes you'll see in some of my plots, they are not very readable an not even appropriate in these contexts, but were left over from another experiment I was playing with 3. it is still liberating current here although it is hard to see - much like during charge when taking the last bits of current slowly, it gives up its last bits of current very slowly too - I never fully discharged the cell 4. note, this is 3 days 5. the cell drops off a little here, I'm not sure if this last bit of current is usable for anything, but I'd like to think the prior portion of the curve is sufficient
Image Notes Image Notes 1. this was a trial to test charging at a lower voltage an to assess the rate of self 1. this shows a trial with Fe2O3 on the iron rod - it is not a viable cell an self discharge, charging works equally well at 1.3V, an 3 days later it is still holding discharges rather quickly - I did not bother with placing a load on the cell the charge at a steady 0.75V 2. self discharge - no load
http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ Image Notes Image Notes 1. the resistor's voltage differential is noisy, I was debugging something, just 1. this is the cell with anode/cathode swapped - so the iron rod is now the ignore it an look at the curve shapes cathode, this does still produce a rechargeable cell, just with less capacity, the 2. the shape of the voltage recovery after taking the load off - the voltage drop electrolyte does not turn blue with this configuration, it is completely clear an seen when a load is applied indicates the internal resistance of the cell the copper seems polished 3. another voltage recovery 4. this photo is of the lower capacity version of the cell seen before the 3 day rest period, I should include a photo of the voltage recovery of the improved cell, but I forgot to take one
step 7: How this 'replica' differs from other attempts Presuming it is a battery, the reproductions I have seen always assumed the following: an acidic electrolyte (lemon juice, red wine vinegar, etc.) with an iron|copper electrode pair contained in a porous unglazed jar. Because the jars and electrodes are present as artifacts, we can assume most aspects of previous reconstructions are accurate, but the evidence for an acid electrolyte or uncoated iron electrode is weaker.
7 mm diameter by 75 mm length iron rod with an Fe3O4 coating instead of uncoated iron The assumption of an uncoated Iron electrode is perhaps not correct. The artifacts (as I understand from written accounts and a few low resolution photos) show a mixture of black and red colored iron - which I assume is Fe3O4 ('black rust') and Fe2O3 ('red rust'), two of the more common oxidation states for iron. I am far from an expert on Iron Oxides, but from what I understand, Fe3O4 does not typically form over Fe2O3 unless placed in boiling water. As an example, I have not seen black rust (Fe3O4) form on an old car covered with red rust (Fe2O3), but that does not mean it is not possible, I've never buried an iron artifact for 2000 years either. However, Fe2O3 (red rust) can work its way into a layer of Fe3O4. Since photos of the artifacts I have seen show a mixture of Fe2O3 and Fe3O4 on the artifact, in my mind's eye, it implies there was originally a layer of Fe3O4 that was later infiltrated by Fe2O3. So, I presume the electrodes were Fe3O4 and not plain iron - it certainly was not Fe2O3, since this does not produce a viable cell. Additionally, as shown in Step 6, Fe3O4 produces a better electrode than plain iron, and if this was a rechargeable battery being used for extended periods, the Fe3O4 coating would provide some protection from the formation of Fe2O3. However, the strongest piece of evidence is that iron of this time and shape would have been forged under a high temperature that exceeded the point of decalescence for low carbon iron 425 F-525 F. Beyond the decalescence point, iron will readily form a coating of Fe3O4. So, by choosing an iron rod without Fe3O4, previous replica creators would need to assume that the Fe3O4 was purposefully removed from the iron rod - but we know that most forged objects of this time retained their Fe3O4 coating. Why: Plain iron would likely oxidize to Fe2O3 (red rust) and this oxidation state does not work well as an electrode. As Fe3O4, the iron is actually protected from the elements and produces a better cell than plain iron, and significantly better than Fe2O3. How: As discussed in step 2, iron is easily converted to the Fe3O4 oxidation state - likely through the forging process, but a piece of already rusted iron can also be boiled in water for a few minutes, or iron can simply be immersed in seawater, all methods work fine, and would have been accessible to civilizations 2000 years ago.
A non acid electrolyte and thus a rechargeable cell The copper electrode is completely oxidized during discharge in the acid chemistry, making for quite a mess (see photo). If an acid electrolyte, the artifacts should show substantial corrosion on the electrodes and in the jar, but none of the archaeological evidence or published accounts I have seen indicated this level of telltale corrosion. The BBC article listed in step 10 mentions corrosion and a test indicating acid, but does not provide any further detail. The corrosion shown in the artifact photographs, actually closely resembles the corrosion patterns I've seen after removing the copper from an alkaline electrolyte (see photo).
If it was an acid chemistry, cider vinegar seems more likely than the lemon juice or red wine vinegar used by some investigators - my understanding is that red wine vinegar was not used in earlier times. Perhaps mashed grapes were used instead, as seen in Arne Eggebrecht's replica demonstration, this would provide tartaric acid, but since acetic acid and citric acid were both known to the Parthians, these are equally possible too. However, an alkaline electrolyte seems just as likely to me, and as I've explained, creates a very interesting battery.
The available construction details also seem to support the possibility of this being an alkaline chemistry. Most investigators, including myself, have wondered why the copper electrode is sealed in the clay jar, since completing a circuit to extract the current is much more difficult - this is puzzling since concealment of the copper electrode does not appear to be necessary with an acid electrolyte. However, with an alkaline electrolyte, the copper electrode is quickly oxidized even when partially exposed to air. Since the artifacts found indicate that the copper was sealed in the vessel with only the iron electrode exposed - this construction detail seems to support the argument for an alkaline electrolyte, not an acid electrolyte, since exposed portions of the copper electrode are less prone to oxidation with an acid electrolyte (see photo).
Why: An acid chemistry means the electrodes are only good for one use. An alkaline electrolyte allows for a rechargeable cell. The cell chemistry is also much less robust with an acid electrolyte, and provides a cell with only 1/5 the capacity of a single charge cycle of the alkaline electrolyte rechargeable cell.
So, maybe I've convinced you this is a rechargeable cell, but how was it charged? Perhaps an earth battery - stick two conductors (Copper, Iron, Carbon, etc. all work fine) into the Earth and you will get around a 1.2 V potential with a few mA of current. I charged my replicas using voltage/current that simulates an earth battery.
How: http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ KOH, an alkaline urine, or perhaps another alkaline substance, are all possible, but my experiments only used KOH. A diet rich in citrus fruits, legumes, and vegetables is known to raise pH and produce urine that is more alkaline - this would have been close to the diet of this time. I've been eating a lot of citrus and legumes lately, so maybe I will retest my urine pH and give it another go. Soap production is claimed to have been present during this time, so it is possible there was familiarity with alkaline chemistries. In my wife's DIY soap book, common lore states that soap was discovered when ash from fire pits drained with the fat from animal renderings into the nearby stream where people washed clothing and other items, and it was noticed clothes were easier to clean - whether this account is true or not, I do not know. However, mixing ash with water is not rocket science. Even today, most KOH is commercially produced by taking the ash form burned wood, soaking in water, and then evaporating the water off to leave KOH crystals. It might make sense to have a pit of water near your night fire, if the ash was raked into the water you should get an alkaline solution that would work well as an electrolyte. Since the Copper sheet was not exposed, the jars may have been placed into a reservoir of this solution (e.g. a hole dug in the Earth filled with urine or ash water) with the iron rod connected to another conductor in the Earth, now you should have an Earth Battery charging station with a ready source of electrolyte replenishment. I'm stretching a little here, but this explanation still seems more plausible than an acid electrolyte. After playing with several replica permutations, I'll reemphasize the electrodes are protected in an alkaline electrolyte, and are oxidized with an acidic electrolyte - furthermore, that the artifacts indicate the copper was isolated in the container, only really matters with an alkaline electrolyte.
Image Notes 1. notice the combination of red an black oxides 2. notice the blue coloration, after immersion in an acid electrolyte my copper does not look like this (see photos in next step) - but this is close to what my copper Image Notes looks like after using an alkaline electrolyte 1. Potassium Hydroxide, an several acid electrolytes that I tested 3. I'm unsure of the permeability of this jar to fluid, but it appears that it might allow the electrolyte to leak out an possibly complete a circuit with the copper cathode
http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ Image Notes Image Notes 1. again the acid electrolyte, but notice the black sludge an corrosion products 1. a red wine vinegar electrolyte before discharge - this is similar to the acid after the cell is discharged, this cell is done an cannot be reused, but it only electrolyte replicas created by previous investigators liberated 1/5 the current of a single charge cycle from my alkaline rechargeable cell replica
Image Notes 1. this copper sheet was used as the cathode in an acid electrolyte, I cleaned up the metal a little with an Al2O3 abrasive to show the difference, but the copper turns fully black if the cell is discharged completely, unlike the alkaline electrolyte, the acid electrolyte oxidizes the copper during discharge 2. this copper was used with an alkaline electrolyte an the photo taken a few minutes after removal -the copper is actually very clean while in the electrolyte, but develops the oxidation layer shown within seconds of exposure to air, an alkaline electrolyte actually protects the copper from oxidation - given the copper is only oxidized when exposed to air with an alkaline chemistry, this may explain why the http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ copper cylinder is completely concealed in the clay jar artifacts, this design constraint has been a puzzling detail unexplainable in other interpretations of the artifacts -partial exposure of the copper electrode to air is not critical with the acid chemistry - but if I left even a small portion of the copper exposed when using the alkaline electrolyte, I had rapid oxidation, so I HAD to seal the copper in a vessel 3. same scenario as the two copper tubes to the right (alkaline electrolyte), but this electrode pair was exposed to air for a longer period - in my opinion, it looks similar to the artifacts shown in the previous step, notice the blue edges interspersed with the black oxides
step 8: Interpretation of the Artifacts Was it a battery? Some say the "battery" is actually nothing more than a scroll holder, others have said it is a Leyden jar.
So what might a battery have been used for during this time?
some speculate it was used as a current source to electrify various objects, either for curiosity or "religious experience" statues controlled by a crafty priest - this does seem nifty, but it would take several batteries to generate a noticeable jolt through the unsuspecting worshiper others have speculated it was used for electroplating gold and that many of the artifacts collected in museums are falsely assumed to be solid gold, although I am unaware of evidence for plated artifacts to support this argument - one researcher claims to have successfully used the batteries to electroplate gold, but other investigators have disputed the veracity of Arne Eggebrecht's claims - despite this dispute (disputes and name calling being all too common in certain academic circles), there are two videos (one with Arne) indicating that electroplating is indeed possible with this battery: 1, 2. I believe that someone could use the battery (or several) to plate gold, but there should also be plated artifacts in existence to support the argument. others speculate that it may have been used in medicine I think there is a possibility that it may have been used to run a homopolar motor. Homopolar motors have a very simple design, consisting of only a current source (the battery), a strip of copper or bronze, and a magnet (e.g. lodestone) - all readily accessible objects. A Homopolar motor was actually the first electric motor built (by Faraday) - but this would imply Faraday was actually late by several hundred years. Copper and Bronze were already being manipulated into various shapes (as seen in the artifacts) and lodestones (naturally magnetized rocks) were likely common and sacred to people of this time for their use as a navigational aid. I've not been able to find any photos or drawings of the bronze and iron artifacts that resembled wires (referenced in the sources listed below), so my argument for a homopolar motor is perhaps stretching, but if the 'wires' are bent properly it may support it. One perplexing aspect of the battery argument is the uncertainty of how the copper electrode was accessed to complete a circuit. According to the sources listed below, the Sassanid style pottery that the electrodes were suspended in with the asphalt seal/stopper was porous not glazed. Part of my reasoning for how a circuit is completed with the battery, depends on a porous shell that allows the electrolyte to seep in during a charge in a pool of electrolyte, and then sweat out during discharge (perhaps, to complete a circuit with a lodestone placed on the bottom of the pot to drive a homopolar motor, as described below, or some other unknown use). If I had access to the 'wire' and other artifacts found near the batteries, or photos of the dig sites, etc. it may be easier to support my claims for a homopolar motor. Until then, I am admittedly stretching to explain how the batteries were actually used, based on the limited puzzle pieces I have available. simple homopolar motor video 1, 2
http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ Image Notes Image Notes 1. a simple homopolar motor built from a magnet, battery, an a piece of copper 1. how a homopolar design might have worked on a baghdad battery 2. a copper wire in close proximity to the magnets below an balanced on one end 2. bronze wire contacting the iron rod an completing half the circuit for the of the battery cell's anode or cathode - I am using a helical design here, but any motor balanced geometry will work - this picture was taken with the wire spinning 3. bronze wire in close proximity to a lodestone placed at the bottom of the jar - around at a fairly high rate of speed the electrolyte leaking down the sides of the vessel complete the circuit with the 3. a magnet at the bottom contacting either the anode or cathode of the battery copper cylinder inside the jar 4. electrolyte leakage through the jar pores 5. electrolyte leakage through the jar pores
step 9: History A better name would actually be "Mesopotamia Battery" since Baghdad was not in use at the time, furthermore, the battery was actually not found in Baghdad, but instead near it in an area called Khujut-Rabua in Parthian times, or Salman Pak in modern day Iraq. However, I will stick with Baghdad since this is how the artifacts are now commonly referenced. I also believe the name Baghdad is important since it would be nice if we identified this region of the world with the hope and centers of learning and science that it once embodied, instead of the cauldron of violence that has plagued its more recent chapters in history.
The date range commonly cited for the artifacts spans 600 years - 300 B.C. to 300 A.D., although I suspect the date of origin might be even earlier. During this time, it was common to conquer people in one region and then move the population (particularly skilled workers) to another, so the artifacts may have originated elsewhere and the people producing them simply enslaved and forced into Mesopotamia. In one famous example, the Babylonians conquered and enslaved people inhabiting what is now Israel (in addition to other regions) and brought them to Mesopotamia to compile bits and pieces of religious text from the area to create the Old Testament - it is likely that technology from the conquered societies came too. Or, perhaps a group that inhabited Mesopotamia even earlier in the timeline is the origin of inspiration (e.g. during the Sumerian reign).
The Assyrians (1200 BC to 612 BC) preceded the Babylonians in Mesopotamia, then the Persians conquered the Babylonians, followed by the rise of Macedonian and Seleucid rule over the Persians, then came Parthian rule (Iran), and then Sasanian rule (also Iranian). In the 7th century, Mesopotamia was conquered by Arab armies and under the Abbasid caliphate became known as Baghdad and Iraq - the cultural and commercial center of the Islamic world. Most of my understanding of the regional history was derived from the Metropolitan Museum of Art summaries e.g. 1, 2, 3 - clearly from the works of art referenced from their site, the inhabitants were highly skilled craftspeople. The Parthians, who conquered Mesopotamia in 138 B.C. ruled over the region until 224 A.D., and whether right or wrong, is the group often credited with creation of the artifacts in many of the archaeological interpretations - perhaps because their rule sits in the middle of the 600 year span (300 B.C. - 300 A.D.) listed as the artifacts' origin date. However, 600 years is quite a margin of error, and I'd like to better understand the reasoning behind this often quoted range. To further complicate matters, the pottery geometry is thought to be of Sassanid origin (224 to 637 A.D.). Pottery geometry could simply be enforced by whom ever is wielding the biggest stick at the time, with the more relevant construction details being conceived/refined earlier in the timeline.
Who's responsible for creating the artifacts? I don't know, but the history certainly seems rather messy. I would guess the inspiration for the artifacts could have arrived along a number of vectors (e.g. conquered populations external to Mesopotamia, or earlier inhabitants), and it would be presumptuous to give credit to any one group (sociopolitical, ethnic, etc.). I feel inclined to give some attention to the history of the "Baghdad battery" since during my research I observed some rather ignorant http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ comments on Youtube and other locations hosting information regarding the artifacts. Ignoring all the complications with pinpointing the origin of these artifacts, in my understanding of the continuous flux of sociopolitical dynamics and population migrations, I find nationalistic pride rather humorous. Let me know if I misstated any of the history.
Image Notes Image Notes 1. Wikipedia map from a Mesopotamia perspective - this is where the artifacts 1. Wikipedia map showing the modern day political perspective - highlighted area were found is where the artifacts were discovered - in modern Iraq it is known as Salman Pak
Image Notes 1. from Wikipedia
step 10: On other published accounts All I have seen are low resolution photos, crude hand drawings, and written summaries of the artifacts. In one case, I think the investigator was blatantly fraudulent in his claims, as I have been unable to reproduce his results. Various accounts of the artifacts:
Wikipedia - Baghdad Battery Mythbusters did a show on this battery but I am unaware of a URL pointing to the video footage - it was shown in episode #29, March 23, 2005. Wikipedia summary of the show: "Ten hand-made terracotta jars were fitted to act as batteries. Lemon juice was chosen as the electrolyte to activate the electrochemical reaction between the copper and iron. (Oddly enough, it was discovered that a single lemon produced more voltage than one of the batteries). When all of the batteries were linked together in series, they produced upwards of 4 volts. Then, the major question was, What were these ancient batteries used for? The show's research staff discovered three possible reasons: electroplating, medical pain relief (through acupuncture), and religious experience. It was discovered that the linked batteries indeed had sufficient power to electroplate a small token. For acupuncture, the batteries produced a random pulse that could be felt through the needles; however, it began to produce a painful burning sensation when the batteries were grounded to two needles at once. For the religious experience aspect of the batteries, a replica of the Ark of the Covenant was constructed, complete with two cherubim. Instead of linking the cherubim's golden wings to the low power batteries, an electric fence generator was connected. When touched, the wings produced a strong feeling of tightness in the chest. Although the batteries themselves had not been used, it was surmised that, due to the apparent lack of knowledge of electricity, any form of electrical sensation from them could equate to the 'divine presence' in the eyes of ancient people. In the end, the Baghdad battery myth was found 'plausible' on all three accounts." "Discovery Channel: The Baghdad battery" video excerpt posted to YouTube (from the 90's?), starts 5 minutes into the video. This cell appears to be a fraudulent replica - the presenter demonstrates a 4.2V cell, but I do not believe these claims. I used a similar experiment setup, and was not able to replicate the results. I found it on this site and they state the following about the presenter: "In this video Jason Martell founder of Godtube and CEO of BooyaMedia performs an on- camera experiment for the Discovery Channel where he is able to consistently generate a positive full 4 volts using a replica he made of the Baghdad battery." An Arthur C. Clarke video with Dr. Arne Eggebrecht - this video has imagery of the actual artifacts and shows Arne electroplating gold to a silver statuette, the http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ replicas produced in this video seem to be the most accurate relative to the others listed, including mine since I did not have access to the pottery, and did not include the copper disc at the bottom (to simplify construction) A History Channel review (?) through a show called "Ancient Technologies" Smith College Replica: I was not able to get the 1.1 Volts they indicate though Writeup summarizing several sources - I included this reference to show how much conjecture there is in the claims one can find on the web when researching this topic Indicates that Willard Grey produced a 2 Volt cell with grape juice, again, I was not able to reproduce this. The BBC numbers indicate Mr. Grey's experiments yielded 0.5V but with Copper Sulfate, and this seems more accurate. BBC article or here Indicates that Dr. Arne Eggebrecht used the cells to electroplate gold in 1978, although the article indicates some have disputed the accuracy of these claims and been unable to reproduce them. Article indicates Arne's cell was 0.87V with fresh grape juice, which is actually not far off from my numbers. Also indicates that Willard F.M. Gray produced a 0.5V cell in 1940 using Copper Sulfate. A notable quote: "The vessel showed signs of corrosion, and early tests revealed that an acidic agent, such as vinegar or wine had been present." but I was unable to find which tests were applied to test the veracity of the claim. Also, Dr Marjorie Senechal, professor of the history of science and technology, Smith College, US states that replicas have been produced that range from 0.8 to 2 Volts, but I am unsure of what electrolyte she is using to make this claim. My own experiments have not generated such high voltages. A recent research paper on the subject Title: "The Baghdad Battery: Myth or reality?" Author: VON HANDORF D. E. states: "unglazed ceramic vessels" Some references to how the history of the battery is currently recorded 1, 2 Just as I was about to publish this instructable I did one last set of Google searches and discovered the most comprehensive summary I have seen on the artifacts - I almost decided to start my write up from scratch, and perhaps I should - it can be found here: I wish I had found this sooner, as the account told in this paper also loosely supports several of my assumptions. According to the listed chronology, artifacts have been found at multiple digs and evidence of bronze and iron wire objects were present at the sites. some notable excerpts: "To answer the first question, one needs to remember that thin wire-like bronze or iron rods were found next to the urns, as reported by the archaeologists. As a point of departure, one may assume that Parthian goldsmiths might have used them as connecting means between the iron rod and the copper cylinder. " Or, as the conductor for a simple homopolar motor? I'd really like to see photos of the artifacts, so if anyone is aware of any, please let me know. "Given the fact that acetic acid and citric acid were known to the Parthians, one may assume that they probably made use of them as electrolytes." In a 1950 dig "excavators had also found copper discs, short thin metal wires, and pieces " "The vase was, the report stated, 12 cm high and contained a copper cylinder of 7 cm height." "They postulated that in the case of the real battery, the entire clay jar was filled with electrolyte, and its porous walls would allow oxygen to diffuse into the cell leading to a continuous flow of current." Or, perhaps electrolyte would seep out and complete a circuit? "One serious flaw with Konigs gold plating hypothesis is the lack of gold-plated items stemming from the excavation site at Khujut Rabbou" Another source I recently found: claims the BBC article as their source, although several bits of information in their article either are not found in the BBC account, or are different, so I am unsure where some of the statements are derived, nevertheless the author makes some interesting claims "Konig also found copper vases plated with silver in the Baghdad Museum, excavated from Sumerian sites in southern Iraq, dating back to at least 2500 BCE. When the vases were lightly tapped, a blue patina or film separated from the surface, which is characteristic of silver electroplated onto copper base. It would appear then that the Parthians inherited their batteries from one of the earliest known civilizations." this would be very interesting, but I'd like to know the source "It also seems that the use of similar batteries can be safely placed into ancient Egypt, where several objects with traces of electroplated precious metals have been found at different locations" again, very interesting, but I'd like to know the source - but then, later in the article there is this statement "One serious flaw with the electroplating hypothesis is the lack of items from this place and time that have been treated in this way." so, I'm confused - they also cite different timelines than I have seen elsewhere "Parthian occupation between 248 BCE and 226 CE"
Image Notes 1. Smith College replica of the battery 2. they show an exposed copper electrode here, but my understanding is that the artifacts indicate a concealed copper electrode
Image Notes 1. a cutaway of the Smith College battery http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ Related Instructables
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Comments
50 comments Add Comment view all 66 comments
strmrnnr says: Feb 21, 2009. 8:36 PM REPLY What do you think of the idea that these were used as an ancient form of electrical blood purification. 50-100mA of current put through the blod stream is said to nuetralize all the viruses, bacteria, and perisites within the blood. 2 hours a day for 21 days. With a said body resistance of 2000Ohms I think that was the real purpose for these.
LkArio says: Feb 10, 2009. 7:26 PM REPLY What do you mean by PotassiumOxygenHydrogen 20%? What's the 80%? How many volts does it give you?
Mr. Green says: Feb 4, 2009. 5:45 PM REPLY im pretty sure you will make several times more power if you use zinc instead of iron.
sonaps says: Jan 17, 2009. 2:51 PM REPLY You should really use the letter "d" when spelling the word "and", it makes it actually work as a sentence.
IanW says: Jan 22, 2009. 8:44 AM (removed by community request)
sonaps says: Jan 22, 2009. 2:01 PM REPLY If taken from english only, by using "an" you are using the wrong form of "a", which wouldn't even be used where it was. I see your points on semantics and wordplay, and still understood the 'ible, but for some reason I am particullarly anal about using words in correct context and grammar.
IanW says: Jan 24, 2009. 12:50 PM REPLY I'm not particular about grammar. Nevertheless, I modified the text to be more readable for you.
IanW says: Jan 24, 2009. 1:10 PM REPLY I deleted the comment above (discussing homophones, etc.) since I reworded the 'ible and did not want to confuse anyone with non existent material. Apparently, when a user deletes their own comment though, this site replaces the comment with: "(removed by community request)" To clarify for any future readers of this 'ible - there was nothing inflammatory, and thus no requests to remove the comment.
sonaps says: Jan 24, 2009. 11:30 PM REPLY Dude, it was still readable, I just thought that you had done it unintentionally.
DrWeird117 says: Jan 23, 2009. 10:50 PM REPLY Would this be a dry cell, or a wet cell? Dry, I would think.
http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ botronics says: Jan 17, 2009. 11:25 AM REPLY Have you tried powering a Joule Thief circuit with it?
cllinker !! says: Dec 15, 2008. 7:16 AM REPLY Neither re-bar nor nails are pure iron. Iron is an element. Many nails are low carbon steel. A softer, more pure steel, is in transformer cores, such as microwave oven transformers. There are different grades of re-bar, some with a higher carbon content and a higher tensile strength. Perhaps the re-bar tested had more of a coating than the nails. "Iron" in early times had various impurities and varied tremendously each time it was produced, some being virtually carbon free and other being steel, iron with carbon and perhaps other elements.
IanW says: Dec 15, 2008. 10:50 AM REPLY Thanks for the comment. Yes, I should reword the statements on 'pure iron'. To clarify, I would recommend a low to mild carbon steel (iron) 0.05–0.3% carbon content. The primary message I wanted to convey is that many nails have coatings that will not work. I believe the rebar tested had some form of coating on it. I could have called it 'steel', but this encompasses a much wider range of alloys, an since the literature always refers to an 'iron' electrode I stuck with this nomenclature.
Unless you're willing to pay a lot of money, almost anything will have some degree of impurities in it, even if we refer to it by it's elemental name. For some of my experiments I have looked at purchasing within greater purity tolerances, for example surepure, but the cost quickly goes up as you consider purity levels. Even 'distilled' water has relatively high levels of contaminants, depending on your application.
IanW says: Dec 15, 2008. 11:22 AM REPLY I replaced the mention of 'pure' with uncoated - let me know if you have an alternate wording that might work better. I decided to stick with iron as the label instead of steel - but can be talked into changing it if a good reason is given. I might include a note on carbon content an other impurities in iron, but some have already complained the text is overly dense, so I will keep it in the discussion for now. Thanks for the comments.
cllinker !! says: Dec 15, 2008. 12:18 PM REPLY So far as I know (I am a blacksmith of 42 years profesional experience and have studdied alloys of iron quite a bit) the cores of transformers are made of the very pure iron alloys, which were invented in the 19 30's by electrochemically purifying iron. Previous to that the purest commercially available irons were the Swedish, Norway and Russian charcoal refined irons that had about .5% impurities of iron oxide and slag incorporated in them and few other impurities. I believe the iron in the transformer cores have some silica added to help prevent eddy currents, but this is from memory and I am not certain of that. Common nails tend to be low carbon mild steel but you will find rivets to be of lower carbon steel used as the steel does not work harden as easily when cold worked as higher carbon steels..
IanW says: Dec 28, 2008. 9:29 PM REPLY Hi clinker - I'm curious if you have any suggestions for creating a better layer of Fe3O4 (beyond the recipe I provide)? I wasn't sure if Blacksmiths work with Fe3O4 coatings.
Besides the relevance to this instructable, I'm currently creating my first welded structure (a home furnishing) from some scrap steel an would like a durable protective finish that doesn't hide the steel. My wife likes the look of "dark wrought iron" (her words) - do you have any suggestions for replicating this look (besides paint)? I was considering Fe3O4, but only if I can develop a better recipe. I have a desk with a welded steel base that has a very durable coating of Fe3O4, but I've never been able to replicate such a good layer - I assumed they were using a different recipe than me. Thanks.
cllinker !! says: Jan 3, 2009. 6:54 PM REPLY to replicate this look there are chemical black oxide products that use some sort of chemical to either change rust to black iron oxide or just leave it on the metal. Gun blackeneing compounds can do it. There is a cold bluing (which is usualy done to a black color) called Van's Bluing
cllinker !! says: Jan 3, 2009. 6:42 PM REPLY Hi Ian. Sorry to be so long in replying. Blacksmiths constantly create FE3O4, and the way it would have been created at the time the Baghdad Battery would have been made was very simple. The iron bar was simply heated to the temperature of descalesence, which varies a little with the amount of carbon and the alloying elements in the bar, as does the purity of the FE3O4, and it old vary for a simple low carbon iron from 475 F to 525 F. Heating above this will make it form faster. The layer will get quite thick and then start flaking off. the flakes are called scale by blacksmiths and were the early source of FE3O4 for things like dying yarn and other processes. It also depends on the amount of oxygen . If heated in a carbon rich or oxygen deprived environment little or none forms. If heated in a oxidizing fire or if a bar over the temperature of descalesence. The temperature of descalesence happens at the same time the iron or steel looses it's magnetism. There is a phase change and the metal stays at the same color for a period of time until this change occurs if heated slowly. An old blacksmith or alchemist would have just heated the bar to a bright orange and it would have the coating. This would naturally occur as the iron bar was hammered to dimension. To remove it the smith would let it cool and would then scrape and or file or grind it shiny. Since iron at this period was always made by forging this always occurred and it was hard to get it shiny. Hope that helps!
http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ IanW says: Jan 6, 2009. 12:52 PM REPLY
Hi clinker - Thanks! The information you provided was very helpful! Re: >An old blacksmith or alchemist would have just heated the bar to a bright orange and it would have the coating > Since iron at this period was always made by forging this always occurred and it was hard to get it shiny. This would seem to further support the argument for an Fe3O4 electrode, which is necessary for the rechargeable aspects of the cell. The replicas previously constructed (in my understanding) had no Fe3O4, but it likely would have been more difficult (during this time) to create iron with the Fe3O4 removed than to use iron straight from the forge. Since I recently (last few weeks) learned some basic metal working skills, I might try forging my own iron electrode - this would make the replica more accurate. I already have several new projects in the queue now, but I'll post back here if I get to it.
Re: >simple low carbon iron from 475 F to 525 F. Heating above this will make it form faster. The layer will get quite thick and then start flaking off. Thanks for this explanation. I'm using an oxy acetylene torch to heat until orange an then bend the metal pieces, an have noticed the oxide formations (an scale when heating for an extended period). So, after welding the structure, I'm assuming I can just heat treat the whole assembly with the oxy acetylene flame to fill in any areas missing a good Fe3O4 coat. Since I just learned TIG I'll probably use this method so I can practice my technique, an then go over everything with the oxy acetylene flame. Let me know if you see any problems.
cllinker !! says: Jan 6, 2009. 4:59 PM REPLY Ian, that sounds like a good idea unless you are welding with stainless for the filler rod, which is very common, and in which case the stainless welded area will not look the same. Stainless will oxidize when hot. My recommendation is to weld a small sample experiment and try and heat the welded area to see if it matches well enough. Any welded or ground area if welded with mild steel rod and or ground will take heating for a little while to match the texture of commercial steel. If you examine hot rolled steel bar you will notice that the rollers from the mill leave particular look on the bar. When blacksmithing this is impossible to match, so typically smiths will hammer the entire surface to make the texture the same or else forge entire bars out on important jobs so everything matches in appearance. I usually do test pieces on jobs to see what the actual appearance will be. If you have problems leave a comment that will notify me on my email and I'll try and give advice.
IanW says: Dec 16, 2008. 8:05 AM REPLY Thanks for the information. I chose nails because they are easy to acquire, an read they had relatively low carbon. I hadn't considered transformer cores or rivets, but I'll keep this in mine next time I need low carbon iron of higher purity.
brian250 says: Dec 28, 2008. 2:59 AM REPLY im thick as a brick with electronics and the like but i understand this instructable,the way it is presented is great,thankyou.
rookie1 says: Dec 26, 2008. 12:01 PM REPLY Great instructable. Very detailed and well written. It reminds me of something I saw when I was a kid(about fifty years back). I saw a local show presented by a museum. People would try to figure out what something was. The object offered turned out to be a plater. It was made up of two jars, one was a jar filled with wine or grape juice with a lead core, I'm not sure if the liquid in the other jar was also acidic or just water but I think it must have been acid of some kind. There was a copper wire running between the two jars and it was wrapped around a piece of gold or silver(not sure which)and there was another copper wire holding an object (metal, also not sure what it would be, maybe copper, bronze or what ever was the going thing back around 2000 years ago)It made a circuit when the object to be plated was put into the second jar. The gold then plated the less valuable metal. I know it's not much to go on but you might enjoy working this out and trying it. Again, a very good instructable.
evanwehrer says: Dec 17, 2008. 6:09 AM REPLY I like that vase
macssam says: Dec 8, 2008. 12:23 AM REPLY you keep loosing track with to many unnecessary links and explanations put everything on one page so anyone can understand ..
kelseymh says: Dec 15, 2008. 12:37 PM REPLY If you want the whole I'ble in one block, use the "view all steps" option, located immediately to the left of the "intro" Step. The links and explanations are not "unnecessary" in principle -- putting things in context, and giving you the opportunity to know where you came from (historically speaking) is always useful and important.
Scattering that information among the "how to steps" did make the project confusing. IanW has gone through and reorganized this I'ble so that the historical information and references are separate from the "how to make it" part. If you still find it confusing, it would probably be most helpful to be specific (which step(s), what information didn't you understand, etc.).
http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ IanW says: Dec 8, 2008. 11:52 AM REPLY Hi, thanks for the comment - but I'm not sure I understand:
Are you saying I should not link to other references, wikipedia, etc.?
Regarding the idea of a "single page", are you saying everything should be listed as a single step? I do think listing the writeup as steps is perhaps cumbersome for the message I am trying to convey. I considered mapping the steps to a more traditional academic publication structure i.e. Introduction, Methods, Results, Discussion. There is some redundancy an cross over between Step 1 an 2 - I considered merging this further. Thanks again for the comment, an I'd be happy to modify the formatting if it would improve readability for others, but I will need more specifics. Please feel free to PM me too.
kelseymh says: Dec 8, 2008. 12:50 PM REPLY The references are great! The detail and background, especially with links to your sources, are an important (and almost universally neglected) aspect of using a lab for teaching.
Having said that, this is an Instructable; philosophically a "how to" recipe for someone to follow, not a research paper. Consider putting the materials list, and (multiple step) assembly instructions for one particular working device first. Each Step should fit comfortably on a single normal-sized screen, and should present one single idea or construction stage.
Tighten up your introduction: just describe what the thing is, with the Wikipedia link, and mention that it has some historical authenticity. Move the rest of the philosophizing toward the end. I'd put the detailed references as the very last step, almost like "annotated end notes."
IanW says: Dec 10, 2008. 1:51 PM REPLY Thanks for the comments, I am in the process of implementing some of your suggestions, please let me know if the modifications have made matters better/worse - or any further suggestions.
regarding: "aspect of using a lab for teaching." do you plan to use this in a classroom setting?
By the way, cool job! - SLAC is a neat facility, an does very meaningful work, although I only have familiarity with the work from the Structural Biology Group
kelseymh says: Dec 10, 2008. 2:52 PM REPLY You asked, "do you plan to use this in a classroom setting?" Not immediately, but it has definite potential for that, especially with the sources included.
Oh, yeah. The SSRL folks do some extraordinarily interesting work -- completely outside my field, but I enjoy reading about it.
IanW says: Dec 15, 2008. 11:18 AM REPLY That would be neat - if you decide to pursue this gradient, let me know if I can provide clarifications or help.
annchanted says: Dec 9, 2008. 8:50 AM REPLY I have always been intersted in the "Baghdad Battery" and I'm looking forward to experimenting at home using your instructions. However, I would like to say that, while very thorough, your instructions were a bit over-inclusive for the layman such as I.
IanW says: Dec 11, 2008. 11:18 PM REPLY I made a few edits that hopefully make the text easier to follow. Please let me know if you have any specific areas that you would like me to clarify further. The intent is to make this easy for the 'layman' to follow, so I'm fine with making further modifications.
kelseymh says: Dec 10, 2008. 2:56 PM REPLY Very nice reorganization!
WhoTookMudshark says: Dec 4, 2008. 8:23 PM REPLY This comment is totally unrelated to the battery, but I bet that you would really like this book I read a few months ago! It's called "Lost History" (by Michael Hamilton Morgan) and it is about all SORTS of great things that happened in Baghdad and the surrounding areas before the renaissance.
It is a great book about the history no one ever hears about from Muslim civilizations of old.
Priemsyone says: Dec 4, 2008. 2:54 PM REPLY Great and interesting information, good to keep an old mind thinking. Thanks
http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ Spaceman-Spliff says: Nov 29, 2008. 11:22 PM REPLY Great stuff... Wanted to know more about this for years but I never had the patience to do all the research myself. Incredibly detailed list of other publications on the subject - if only everyone were as diligent! Keep up the good work.
IanW says: Dec 1, 2008. 3:46 PM REPLY Thanks - since the artifacts are a popular topic on various blogs an elsewhere, I will try to update the sources section in Step 1 as new information comes to my attention. I just added another account published a few days ago. Although I find it difficult to separate fact from fiction with much of the information available...
scafool says: Nov 27, 2008. 10:45 PM REPLY Very nice, because now I know how to make "a proven to work" battery out of fairly primitive materials. Even better is that it is a rechargeable alkaline.
AnarchistAsian says: Nov 25, 2008. 8:37 PM REPLY ha ha, i love those!
kelseymh says: Nov 24, 2008. 3:34 PM REPLY This technology was also presented and discussed on [http://en.wikipedia.org/wiki/MythBusters_(season_3)#Baghdad_Battery Mythbusters] several years ago (episode #29, 2005).
IanW says: Nov 25, 2008. 10:50 AM REPLY Thanks for the comment. I mention their presentation in the sources section - but am not aware of any video footage accesible via the web. I added the episode number reference that you provided. If I recall correctly, their cell used lemon juice as the electrolyte - an alkaline electrolyte greatly improves the chemistry. I have limited satellite access from my current location, an will try to check for comments over the next few days.
Lithium Rain says: Nov 24, 2008. 6:38 PM REPLY I'm starting to think nobody watches them anymore, only claims to...
strmrnnr says: Feb 21, 2009. 8:37 PM REPLY I think they have gained the same reputation as CNN and 60mins. Bought off by the corporate machine.
kelseymh says: Nov 24, 2008. 6:55 PM REPLY Well, I have to voice my own complaint that the actual science content (i.e., numerical analysis and hypothesis testing, as well as just explanation) has gone down substantially in the last two or three seasons. The shows sometimes seem more about just explosions and less about investigating something unusual or unexpected.
AnarchistAsian says: Nov 25, 2008. 8:40 PM REPLY yeah, of course, that's what the show was meant to be, because most people are stupid these days, and wouldn't care...
whatever, anyone who would care, would already know, right?
temp says: Nov 29, 2008. 4:49 PM REPLY me like when they make go BOOM.
AnarchistAsian says: Nov 29, 2008. 8:08 PM REPLY doesn't everybody?
Boom Boom Boom BOOM BOOM BOOM boom boom boom boom
kelseymh says: Nov 26, 2008. 8:54 AM REPLY Not stupid, just with poor science education and little or no education in critical thinking (the outcome of budget cuts to U.S. education and "teaching to the test" requirements). The way the U.S. media present science and pseudoscience in a "balanced" way, as though they were political opinions, makes it even worse.
I've done a fair bit of public speaking on science (and read I'bles discussions :-). It is reassuring to me how many people are interested in science and have thoughtful ideas and questions. They just don't have the facts, or the training to evaluate assertions, to give them a good foundation.
Lots of people would care, and not know. That's why the early seasons of MB were so great, in my opinion -- they didn't just make claims, they showed the process of science. http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/ AnarchistAsian says: Nov 26, 2008. 11:54 AM REPLY well, yeah, but i mean, there are a lot of stupid people these days. at least at my school When i moved to houston in 5th grade, people were fighting over disposable plastic test tubes to do "testing" at home... No, cups weren't good enough to do 5 year old stuff, they needed "fancy" stuff...
it's a little sad... I'm just glad my dad is a physicist... And my new science teacher actually makes us figure things out, instead of just telling us. We're making rube goldburg machines after thanksgiving, sounds fun... view all 66 comments
http://www.instructables.com/id/Building_a_quotBaghdad_Batteryquot/