sis_11_2*:Layout 1 23.04.2009 14:03 Uhr Seite 52 Image courtesy of Bryngelzon/iStockphoto Take the weather with you
Karen Bultitude introduces a set of simple, fun and memorable demonstrations using everyday ingredients to explain meteorological phenomena.
nderstanding our impact on the suggestions for activities related to you should see a cloud form in the Uenvironment is increasingly environmental sciences can be found bottle, then disappear when you important, with both scientific and onlinew2. squeeze it. societal implications now covered in 4. Pass the bottle around the class, Cloud in a bottle various parts of most school curricula. instructing them to squeeze and With so much talk about climate Create your very own mini-cloud. release the bottle themselves to see the cloud. change, it is useful to learn about Materials some of the atmospheric phenomena You can also watch a video of the w3 that actually make up our climate. · A 500 ml colourless plastic bottle activity online . with cap The following demonstrations help How does it work? clarify some aspects of these phenom- Water · Clouds are formed when water ena and bring the concepts to life in A teaspoon · vapour in the air cools down due to an engaging and memorable way. · A match the expansion of the rising air mass, They were developed as part of the and then condenses to droplets on w1 Instructions British Council’s ZeroCarbonCity condensation nuclei such as dust par- campaign to support teachers and sci- 1. Place approximately one teaspoon- ticles, ice or salt. In this demonstra- entists throughout the world in ful of water into the plastic bottle tion, the condensation nuclei are pro- explaining basic concepts of environ- and swirl it around inside the vided by the smoke from the match, mental science. The demonstrations bottle. which contains particles of uncom- can be used in a variety of ways: indi- 2. Light the match and make sure it is busted hydrocarbons. The tempera- vidually, to emphasise particular con- burning well, then drop it into the ture is changed by squeezing the bot- cepts during class; as a collection, for bottle. tle: the amount of air within is con- example as a workshop or demonstra- 3. Quickly screw the cap on tightly, stant, but squeezing the plastic bottle tion lecture; or as set tasks for stu- then squeeze the bottle with your lowers the volume of the gas, raising dents to complete themselves. Further hand five or six times, after which the temperature slightly. When you
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Projects in science education
stop squeezing the bottle, the volume ful sunset. There are some concerns Instructions increases, thereby causing a slight that air pollution will therefore have a 1. Fill the bottle about one-quarter full detrimental effect on the weather, lowering of the air temperature with the hand wash, then add a few since more air pollution leads to inside. If the air inside the bottle has a drops of food colouring. relatively high humidity (which is increased cloud formation, which 2. The demonstration won’t work if ensured by adding the teaspoonful of could in turn lead to more rain in cer- the mixture foams: turn on the tap tain areas and a significant change to water at the beginning) then the tem- so that only a trickle of water is wider weather patterns (floods in perature drop is sufficient to cause the coming out, then carefully fill the some areas; droughts in others). water to condense on the dust parti- bottle up to the very top. cles, forming a cloud. Whirling orb 3. Screw the lid onto the bottle, and Links to atmospheric phenomena This is a beautiful and fascinating swirl the bottle around a few times (with the lid pointing upwards). If Next time you see a fantastic sunset demonstration of turbulent weather any foam forms, take the lid off and over an urban area, take a moment to effects. trickle some more water into the think about what is causing the beau- Materials bottle, letting the foam run over the tiful colours: its origin actually lies in edge. Put the lid back on (tightly). the tiny smoke particles and other · A small clear plastic bottle (the 4. Move the bottle around: you will be pollutants that have been emitted into more rounded the bottle, the better), able to see turbulence patterns the atmosphere. Just like in the plastic including a tight-fitting lid (streaks and swirls) in the liquid. bottle, these smoke particles encour- · Liquid hand wash (soap) that con- age water droplets to condense tains glycol stearate How does it work? around them, forming clouds. The Food colouring Moving the bottle around causes scattering of the Sun’s rays amongst · the soap and water mixture inside to the clouds is what creates the beauti- · Water (from a tap) move. The glycerol stearate makes the
Images courtesy of Jonathan Sanderson
The whirling orb in action
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Images courtesy of Elin Roberts and Jonathan Sanderson
Making a teabag rocket
patterns of flow visible, so you can Instructions be enough to overcome the force of see the directions in which different gravity keeping the teabag on the 1. Undo the teabag, removing the staple parts of the mixture are moving. saucer, and so it will lift up. and string and disposing of the con- Smooth lines forming in the liquid tents (the tea). Open up the teabag so indicate laminar flow, which occurs Links to atmospheric phenomena it is a long cylinder of paper. when the liquid is moved slowly. If Thermals are the basis for various 2. Stand the open teabag upright on you make the liquid move faster (or weather patterns. The Sun heats up the saucer or plate. change the direction suddenly) then the land, causing thermals to spiral 3. Use the match to light the top of the the observed lines of fluid become upwards. Thunderstorms are giant teabag. more complex: this is turbulent thermal systems, and the vortex for- flow. 4. Watch as the flame burns down the mation associated with tornados and teabag: just before it reaches the hurricanes is also based on thermals. Links to atmospheric phenomena saucer, the teabag will lift off. The As an effect of global warming, more The Earth’s atmosphere is a kind of flame will go out, but the teabag thunderstorms are expected to occur. fluid that moves much like the liquid will keep on rising. Tame tornado inside the whirling orb. Winds interact Tips for success with the spinning atmosphere and cre- This is a good visual demonstration This demonstration works best in a ate complex circulation patterns. of how tornadoes form. still room where there are no air cur- Understanding the general circulation rents, away from windows or air con- of the atmosphere is fundamental to Materials ditioning. the work of many different areas of Two large (~2 l) empty soft drink Be careful to ensure that you use · climate change science – for example, bottles (must have rounded necks) the right sort of teabag – it must fold in understanding and reducing the out to produce the long cylinder of · A ‘tornado tube’ adapter (available effects of both hurricanes and pollu- paper. Teabags without a string from many science centres and tion. w4 attached usually won’t work. museums or online ) If you can’t find a tornado adapter, Teabag rocket How does it work? try placing a large washer (either This is a good visual demonstration of The burning teabag heats up the air metal or stiff rubber sealing ring) thermals – rising currents of warm air. immediately above it. Hot air rises, so between the two bottles and fasten- Materials the warmer air will gradually rise up ing it all together with tape – the idea above the teabag, creating a rising is to join the two bottles to gether so A traditional-style teabag · current of warm air – a thermal. that the water can flow between · Matches When the teabag has burnt down far them and they remain rigid (see · A saucer or plate enough, the lift from the thermal will images on page 55).
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Projects in science education
Images courtesy of Nicola Graf
Building a tame tornado with a large washer instead of a special adapter
Instructions mon to make the mistake of twist- thunderstorms, where air starts mov- ing the contraption around the ing in a circle. Updrafts and down- 1. Fill one of the soft drink bottles point where the bottles are joined drafts within the thunderstorm force with water until it is approximately together). the rotating column of air to become half full. vertical, creating the tornado. An 2. Screw the ‘tornado tube’ adapter · Make sure you replace the plastic increased number of thunderstorms is into the empty bottle. bottles if they get too bent out of shape – they need to be round to therefore likely to cause more hurri- 3. Invert the empty bottle and screw make a proper vortex. canes and tornadoes to form through- the opposite thread of the ‘tornado out the world. tube’ adapter into the water-filled · Leakage problems are common. bottle. Try using cling film or plumber’s Web references 4. Turn the whole contraption (PTFE, polytetrafluoroethylene) w1 – Further information about the upside-down. tape to better seal the adapter around the bottles. British Council’s ZeroCarbonCity 5. Grasp the top and middle of the campaign is available here: contraption and spin it in a circular How does it work? www.britishcouncil.org/ motion – either clockwise or count- This demonstration produces a vor- zerocarboncity.htm er-clockwise. tex similar to those observed in w2 – The full set of ten demonstra- 6. Once a vortex (whirlpool) forms in cyclones, tornadoes and whirlpools. tions, including a Russian transla- the upper bottle, stop spinning – As the water spins around the bottle, tion, is available here: you should see the vortex form there is a downward pull formed due www.scu.uwe.ac.uk/index. throughout the liquid, and continue to the water passing through the php?q=node/180 as long as there is liquid in the opening into the empty bottle below. upper bottle. The initial small rotation caused by w3 – To watch a video of the cloud in You can also watch a video of the spinning the bottles gains speed as a bottle, see: w5 activity online . the water is sucked through the open- www.physics.org/interact/ Tips for success ing. As the rotation speeds up, the physics-to-go/cloud-in-a-bottle/ vortex forms. index.html If the vortex doesn’t work straight · w4 – For an international supplier of away, try reducing the size and Links to atmospheric phenomena ‘tornado tube’ adapters, see: increasing the speed of the circles One of the predicted impacts of you are making. Make sure that the climate change is global warming: www.101gear.com bottles are held vertically and your warmer air temperatures mean that w5 – To watch a video of the tame circles are centred about the long thunderstorms are more likely to tornado, see: axis of the contraption (it is com- form, and tornadoes are formed in www.physics.org/interact/
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Image courtesy of CDH_Design / iStockphoto
Building a tame tornado with a ‘tornado tube’ adapter
This article provides fun physics experiments with a The article is also suitable for interdisciplinary link to the teaching of environmental sciences and activities involving science and English. particularly of meteorological phenomena, which are surprisingly not too large in scale to be simulat- Activity Related topics within School level the science curriculum ed in a classroom. The proposed demonstrations are simple, cheap and Cloud in a The water cycle Primary/secondary bottle States of matter and phase Primary/secondary attractive, and at the same time don’t require special transitions (heat transfer, equipment, can be proposed to students of different thermodynamics, chemical ages, and can be expanded at different levels. bonding) Water physics (specific heat Secondary I recommend this article to science teachers from capacity, heat of fusion, heat primary to secondary school. The experiments are of vaporisation) suitable as warm-up activities to address various Atmospheric physics: Secondary topics within physics and earth science curricula, humidity (absolute and relative), temperature such as: states of matter, phase transitions, gases, (adiabatic heat gradient), fluid dynamics, Earth’s atmosphere (temperature, pressure, dew point, clouds pressure, humidity, clouds, general circulation, (formation classification) Whirling orb Earth’s rotation and Coriolis Secondary cyclones and tornadoes, for example), air pollution and effect (ocean currents) (earth science) and climate change. It can also be used to start a dis- tame tornado Ocean currents, atmospheric cussion on climate change and sustainable develop- currents and energy ment. exchanges on Earth General circulation of the Comprehension questions: atmosphere, winds, cyclones 1) Which of the following is not an example of a and anticyclones Cyclones: hurricanes, condensation nucleus: tornados, mid-latitude a) dust particle b) gas molecule c) ice crystal cyclones Energy, heat and temperature Secondary d) salt particle Teabag rocket Heat transfer and 2) Thermals are: thermodynamics Gas physics a) sinking currents of warm air b) rising currents Density of cold air c) sinking currents of cold air Atmospheric physics d) rising currents of warm air Fluid dynamics REVIEW Guilia Realdon, Italy
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Projects in science education
Images courtesy of Elin Roberts and Jonathan Sanderson
physics-to-go/tame-tornado/ index.html w6 – For more information on the STEM Directories, see: www.stemdirectories.org.uk Resources Climate Challenge is an online game with associated support resources developed by the BBC: www.bbc.co.uk/sn/hottopics/ climatechange/climate_challenge Oxfam have developed a week of activities about climate change to be run with children ages 9-11: www.oxfam.org.uk/education/ delivers the UK-wide STEM resources/climate_chaos Directoriesw6, a government-funded NASA has an excellent range of initiative to provide STEM (science, animations available relating to technology, engineering & mathemat- climate change: ics) teachers and lecturers with a www.nasa.gov/centers/goddard/ reliable and comprehensive overview earthandsun/climate_change.html and signposts to enrichment and enhancement activities across the UK.
Dr Karen Bultitude is a senior Lecturer at the University of the West of England, Bristol, UK. She has deliv- ered the demonstrations outlined here (including training teachers and scientists in their use) in numerous countries including Russia, Bulgaria, Latvia, Costa Rica and Greece. She is a member of the consortium which
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