sign in sign up
<<
Home , Dry cell, Lemon battery

The Battery Challenge

Grade Level • Understand how much approximately 6 million power it takes to run an million million 3rd through 8th electric car (6,000,000,000,000,000,0 00) electrons flow through Background the bulb each second Materials (write this number on the

The power behind board). The flow of • 4 D-size batteries electricity comes from one electrons is called an • 4 of the smallest things electrical current and is • 4 - known to science -- measured in Amperes --- in shape of a spike, 3- electrons. Electrons are when 6 million million 5 cm. long tiny particles within atoms million electrons flow • 4 electrodes - in that have a minute electric through an electrical circuit shape of a spike, 3-5 charge. If a million million in one second, the current cm long (1,000,000,000,000 -- is approximately 1 Ampere • Multimeter for write this number on the (6,000,000,000,000,000,0 measuring DC chalkboard or white 00 electrons = 1 Ampere). and low (-.0001 A) board!) electrons were current lined up, they would barely Electricity is used for many reach across the head of a important things in our Objectives of this pin. When lives: light, heat in our homes, computers, etc. In activity flows through a wire, these tiny particles actually order for electrons to move

surge through the metal of (and for us to get electrical • Learn how a chemical the wire -- just like water current to power our reaction can produce flows through a pipe. It favorite devices), a source electricity takes an unbelievably of energy is needed. This

large number of electrons energy may exist in • Create a wet-cell battery flowing through a wire to various forms: mechanical

light a bulb -- motion, light, heat, or a . Chemical energy is the engineers use these source of power in measurements: Engineers abbreviate batteries. The simplest these electrical quantities batteries consist of two In an analogy to water as V (voltage), I (current), different metals flow, a battery is like a R (resistance). These are (electrodes) floating in a paddle wheel that raises related to each other as bath of acid. Atoms from water up to a height --this follows: V = I x R. one metal travel through is voltage. Electrical power (P) is the acid to the other metal related to voltage and releasing electrons. As water flows through a current as follows: Eventually, when all the pipe, electrons flow P = I x V. mobile atoms have been through the filament of the transferred, no additional light bulb this is current. Activity electrons may be released, and the battery As water flowing downhill • Explain the goal of the is dead through a pipe encounters exercise: To calculate friction, electrons flowing how many lemons it Engineers make through the filament of the would take to run an measurements when they light bulb encounter friction electric car. are working with electricity. and release energy -- this

They measure voltage, is electrical resistance. • Explain that electric current, resistance and cars run on very large power. By considering a The entire process batteries and not simple circuit, a battery converts electrical energy internal combustion connected to a light bulb, to light energy and heat engines like regular one can see how energy. cars. So what are lemon so that batteries? approximately half of the is still • Show the students a protruding out. typical . Ask them how it • Instruct them to do the works. same with the copper electrode. Have them • Explain that, within a space the electrodes battery, a chemical about 3 or 4 cm apart. reaction takes place between an • Go around to each and electrodes. An group with the electrolyte can be a students will create a multimeter. Set the liquid acid or a dry wet cell battery using multimeter to read DC chemical. The the juice of a lemon, voltage, and measure electrodes are two which is a mild acid, the voltage (V) of the different conducting as the electrolyte. battery. Hold the materials, such as display or needle of metals. Show the • The voltage (V) and the multimeter so that theory diagram of the current (I) delivered by everyone can see and electrodes in an acid the lemon battery will read the numbers. The bath. be measured using a battery voltage (V) multimeter. Show the should read • The chemical reaction multimeter and the approximately 1.5 causes electrons to be model diagram -- show that this displaced, and these depicting the circuit is written on the side electrons have the through the lemon and of the battery, potential to do work. the multimeter. confirming in the The potential energy students' minds that stored in the electrons • Divide the class into the multimeter works is known as voltage smaller groups. Give properly. If the reading (V). The flow of each group a D-size is less than 1.5 Volts, electrons through a battery, a lemon, a tell them the battery is wire is known as copper electrode and old and has lost some current (I). The power a zinc electrode. of its energy. (P) delivered by a battery is measured by • Ask one student to be • Read the voltage (V) multiplying its voltage a designated recorder across the electrodes times the current. On a and stand by the of the lemon battery. chalkboard or chalkboard or The multimeter should whiteboard, write whiteboard to record read approximately I P=V x I. the results as they are . Digital LCD called out. displays might show • Batteries come in two 0.997 Volts or 0.989 categories: dry cell • From the front of the Volts. Have the and wet cell. Dry cells room direct each designated recorder (such as group to first press put this under a batteries) are the down on the lemon column labeled "V' on alkaline batteries that and roll it on the table the chalkboard. The use a powder to get the juices readings will be chemical for an flowing inside. averaged. electrolyte; wet cells (such as car batteries) • Have the students • Set the meter to read use acids as the insert the zinc DC current, and take electrolyte. The electrode into the the reading across the electrodes of the think about that for a Credits lemon battery. The minute. reading will be This activity was provided approximately 0.0001 • Ask if it makes sense by IBM research engineers Amperes. Ask the to use lemons to who invite you to see recorder to put this power a car. What are what's going on at reading in a separate some of the pros and www.research.ibm.com. column labeled "I" on cons? the board. Again, the readings will be Pros - does not pollute, averaged. renewable energy source, electric cars are quiet etc. • After taking readings from each small group, Cons - cannot recharge look at the recorded lemons, heavy, expensive results. Take the (25 cents per lemon = $15 average of the million) readings. • Explain that the point • Multiply the average was to actually see if voltage (V- 1. 0 Volt) lemons should be times the average used to power cars, current (1-0.0001 but rather to explain ampere) to find the the principles of average power (P- batteries and 0.0001 watt) delivered electricity; that a by the battery. simple lemon could be made into a battery by • Explain how it takes creating a chemical 100 watts to power a reaction, and that we 100 watt light bulb. can apply simple The more the wattage, mathematical formulas the greater the power and determine how consumption. Ask the much power we can students to calculate generate and how how many lemon much it would take to batteries would be run the car. required to power the 100 watt light bulb Conclusion [Answer: 100 watt / 0.0001 watt = I million These are the problems (1,000,000) lemon engineers and scientists batteries]. face. They ask questions, develop a theory or a • An electric car model, test out their ideas requires 6000 W of and draw conclusions. In power to run. Ask the order to do this however students to calculate you need a strong how many lemon background in math and batteries would be science. required to power the electric car. [Answer: 60 million (60,000,000) lemon batteries, employing 60 million lemons!] Let, them