Science Experiments on Renewable Energies2013 - 2015 1 Summary How to make a Volta's battery.3 Potato battery..5 Solar collector..7 Understanding the air pressure..8 Radiator butterflies.9 Salt water battery.11 How to produce dihydrogen using water?........................12 Lighting a LED using the air!..........................................14 Eolic motor with Coca Cola paper cup.17 Seawater desalination with solar energy .18 The warmth of the earth..21 How to make a water turbine23 Parabolic concentrator.25 How to make a hovercraft..27 Mini hydro power..28 Living on air30 Coca Cola & Mentos power...32 Build a windmill!................................................................34 How to make a wind turbine.35 Homopolar motor.37 Chemical energy & soda rocket..39 Renewableenergy from taking a shower42 Science Experiments on Renewable Energies2013 - 2015 2 Science Experiments on Renewable Energies2013 - 2015 3 HOW TO MAKE A VOLTA'S BATTERY proposed by French Team To make a Volta's battery, we need: a piece of zinc, staples, a piece ofcopper,anelectricwire,vinegar,saltandapieceoflace.Wewill use this battery to light a LED.

Materials to make a Volta's battery 1.How to build the Volta's battery: First, we place staples on one side of the lace and an electric wire on theotherside.Then wesoakthe pieceoflaceinthevinegar/salt mixture. Finally we have a battery: A Volta's battery Science Experiments on Renewable Energies2013 - 2015 4 WebuildthreemorebatteriesandwelightaLEDwiththesefour batteries in series. Four batteries to light a LED 2.How it works: Themetalsarecomposedofatoms.Intheseatoms,thereare littleparticlescalledelectrons.Whentheseelectronsaresetinto motion, electricity is produced. By placing two different metals in an acid and conductive solution, we produce chemical reactions allowing the circulation of electrons. YoujusthavetolinkthesetwodifferentmetalstoaLED,for example, to put the electrons in motion and see the LED lights. Schema presenting the principle of the battery Science Experiments on Renewable Energies2013 - 2015 5 The metal receiving the electrons will be the positive terminal. The metal from where the electrons leave will be the negative terminal. In the case of a zinc/copper battery, the positive terminal is the copper. This terminal is called the cathode. The negative terminal is the zinc. This terminal is called the anode. POTATO BATTERY proposed by Romanian Team Thisisasimpleandinterestingexperimentwhichshowsthat potatoescanbeuseindifferentways.Ifyourunoutofbatteriesin your home, you can do one by yourself using potatoes. For this experiment you will need: - copper isolated wires; - copper tins; - galvanized tins; - one low voltage (1-2V)LED; - 5 or more potatoes. Using a soldering iron you can solder a copper tin with a galvanized tin.FortheLEDyoucanletjustonewirewithcopperandonewire withgalvanizedtin.Thenyouwillputineachpotatodifferent electrodes, like in the picture: Science Experiments on Renewable Energies2013 - 2015 6 WhentheLEDisconnected,youwillhavethesurprisetosee that it is light! So the potato battery works! Apotatobatteryisan electrochemicalbattery,otherwiseknown asanelectrochemicalcellinwhich chemical energyisconverted to electricenergybyaspontaneouselectrontransfer.Inthecaseof the potato, the zinc electrode reacts with the copper electrode.Youcanreplacethepotatoeswithotherfruitslikelemonsor oranges. You will see that the same will happen!

Science Experiments on Renewable Energies2013 - 2015 7 SOLAR COLLECTOR proposed by Italian Team Solarthermalenergy (STE)isaformofenergy andatechnologyfor harnessingsolarenergyto generate thermal energy. Aims Theaimistoproduceasolar collectorwithpoormaterialsand easytorealize,forstudentsfrom9 to 18 years old. Materials/ Instruments Glass tube ( 1 ) ThermometerCork ( 1 ) Water Alluminum paper ( 1 )Plastic tube ( ) Lamp ( 1 ) or natural sun Carton( 1 paper )Science Experiments on Renewable Energies2013 - 2015 8 Realization You have to cut the plastic tube in two equal parts, after you have tofilltheglasspipewithwaterandtoclosewithacork.The aluminum paper must cover the internal part of the plastic tube, with thecartonpaperyouhavetobuildasupportforthetheglasstube and place it inside the plastic tube. The thermometer inside the cork is in contact with the water. Physical effect Whenthesolarradiation,orthelamplight,arriveonthe aluminumpapersurface,itisreflectedintheplastictubefocus, where is placed the glass tube. The radiation warms the water inside and the temperature increase. UNDERSTANDING THE AIR PRESSURE proposed by Turkish Team Materials: Boiled Egg Bottle Paper Fire Wewillfirethepaperandputitintothebottle.After,wewillput the egg on the bottle. We will see that the fire enable to expansion of air. Afterafewtime,wewillseetheeggwillhaveamotionup and down. Science Experiments on Renewable Energies2013 - 2015 9 Afterthefireextinguished,theeggwillfalldownintothe bottle. Becauseofthehighairpressureandlowairpressureinthe bottle, the egg fall down. In the experiment, we understand the air pressure around us. RADIATOR BUTTERFLIES proposed by Dutch Team Dobutterfliesusetheirwingsonlytofly and show their beautiful colors? What do you need? 2 identical empty tins tin foil Science Experiments on Renewable Energies2013 - 2015 10 scissors tape thermometer Experiment: Cut two strokes of tinfoil: The first has the same height as the tin and the length needs to be 5 times the outline of the tin. Thesecondstrokehasthesameheightasthetinandthe same length as the outline of the tin Wraponetinwiththelongstrokeoftinfoil.Every3cmyouhave to fold the foil in the shape of a wing of 6 cm wide (as in the picture). Stickthe(3cm)partstothetinwithtape.Wraptheothertinwith the small stroke of tinfoil and stick with tape. Fill a jug with warm tap water. Wait a minute until the water in the jug has the same warmth everywhere. Fill the two tins with the warm water to the same height. Measure the warmth in both tins every five minutes. Explanation The water in the tin with the wings cools down more quickly than the water in the other tin. Iron and aluminum are metals. Metals are very good conductors of heat.Abiggeropeningatthetopwillgivemorewarmthtotheair. Thewarmthescapesnotonlyfromthetop,butalsoatthesidesof the tinandthrough the tinfoil.Thesurface of thetinwith thewings in contact with the air is bigger than the other tin. So the water in the tin with wings will cool down more quickly. Use Likethewingsofthetin,thewingsofabutterflyhavealarge surfacetoexchangeheath.Duringsunnybutcoldweatherthe butterfly opens it wings to absorb the warmth of the sunbeams. If it Science Experiments on Renewable Energies2013 - 2015 11 is cold and cloudy a butterfly folds its wings to lose warmth as less as possible. The radiator of a car cools down the engine. It is constructed from metalbladeswhichpassonthewarmthoftheenginetotheair.In this way the engine does not get over heated.Radiatorsathomeoftenhavewings too,toenlargethesurface toexchangetheheathofthewarmwaterintheradiatortotheair. The wings make optimal use of the warm water in the radiator so we have nice warm rooms! SALT WATER BATTERY proposed by LithuanianTeam Batterieshavebeenmadewithmanydifferentchemical compounds. Scientists often try to make batteries that provide more energyandlastlonger.Manyofsuchhighqualitybatteriesare commerciallyavailabletoday.Theyareusedinflashlightsand electronicdevicessuchasradios,watches,computersand calculators. Making a battery is always an exciting science project. Your home madebatteriescanbeusedas chemistry,physicsorelectricity project.List of materials you need: 1.Miniaturelightbulb(low voltage, low current)- LED 2.Miniaturebaseforlight bulb 3.IronElectrodes(bigiron nails) 4.Copper Electrodes 5.Wires 6.8 plastic cups of saltwaterScience Experiments on Renewable Energies2013 - 2015 12 How the battery is made? Abatteryismadeoftwodifferentelectrodesinsertedina chemical compound. A chemical reaction between the electrodes and thechemicalcompoundproduceselectricity.Forexampleifyou insert a copper rod and an iron nail in a cup of salt water, that will be a battery. Inthisexamplecopperrodandironnailaretheelectrodesand the salt water is the chemical compound or electrolyte. The problem is that the electricity produced by such a battery is too little and has nopracticaluseandyoucannotuseittolightupalightbulb.The saltwaterbatterydescribedinthisprojectguidecanlightupalight bulbforafewseconds.Whenthelightgoesoff,youcansimply empty the used salt water and add fresh salt water to get light again.TIP:Byaddingasmallamountofhydrogenperoxideyoucanget more light and the light will last longer. HOW TO PRODUCE DIHYDROGEN USING WATER? proposed by French Team Dihydrogenisagasusedasfuelinspecificvehicles.Itisaclean fuelduetotheproductionofwaterduringthecombustion,andno carbon dioxide. Experiment To produce dihydrogen, you need to: Fill a container with water and add salt (an electrolyte). Filltwotesttubeswiththatmixture(calledasolutionin chemistry) Taketwonails(ortwozincsticks)andplaceoneofthemin each test tube upside down in the container. Science Experiments on Renewable Energies2013 - 2015 13 Putawirebetweenminus(-)terminalofabatteryandone nail. This nail is called the cathode.Putawirebetweenplus(+)terminalofthebatteryandthe other nail. This nail is called the anode.Wait and look at the experiment. Afterawhile,littlebubbleswillappearonthenails.The dihydrogen will be produced on the cathode. Dioxygen will be produced on the anode. Afteronehour,ifthereisalackofgasinthetesttubes,wecan add salt in the solution. BE CAREFUL!!! Usingsaltaselectrolytewillproducechlorine(toxicgas)onthe anode. It is important to produce few quantities of gas and to work in an aerated room. Dihydrogen is an explosive gas. As we produce small quantities, it isarmless,but,tocheckifwehavereallyproduceddihydrogen,we can approach a lighted match to the test tube, far from our body and face.Wewillhearashort detonationandseeaflame goingoutofthetube.Sowe havetodothisvery carefully!!!! Simple explanation Electriccurrentbreaks watermolecule(H2O)to separatehydroxideion(OH-) from hydrogen ion (H+). Science Experiments on Renewable Energies2013 - 2015 14 Hydrogenionsacceptelectronsfromthecathodeandform dihydrogen (H2). Hydroxydeionsloseelectronsnexttotheanodeand,afteran oxydoreduction transformation, they form dioxygen (O2). We produce dihydrogen twice more than dioxygen because in the water molecule (H2O), there is twice more hydrogen (H) than oxygen (O). What is an electrolyte? Pure water isn't a good conductor. To improve its conduction, we can add salt or use a basic or acid solution instead of water. LIGHTING A LED USING THE AIR! proposed by Romanian Team For this experiment we will need: -Copper wire -A small cylindrical plastic support for the wire -A metallic ax with isolation at the middle -Some small magnets -Small pieces of wood -A piece of cardboard to make a propeller -Good universal glue Science Experiments on Renewable Energies2013 - 2015 15 -A plastic bottle -Water -A low voltage LED How to build the device: Firstyoutakethecylindricalplasticsupportandtake2holesfor themetallicax.Dontforgettoputasmallrubberisolationatthe middle of the ax. Fix the ax with 2 plastic pieces. Check if the rotation oftheaxisgood. Thenmakeacoil withthecopperwire andattheendsput theLED.Inthe middle,ontheback rubbersupportyou willhavetogluethe small pieces of magnets, symmetrical.Makeacardboardpropellerwhichmustfitatthelongestaxend. Check again the rotation of the ax. Forthewood supportofthecoil, youhaveto measurethe dimensionsofthe bottle cap. Takeaholein theplasticcapand glueitonthewoodsupportlikeinthepicture.Alsogluethecoil, taking care that the propeller must be exactly above the plastic cap.Science Experiments on Renewable Energies2013 - 2015 16 Then cut the plastic bottle in 2 pieces, one to fix in the cap and the other to fill with water. The result must be like in the picture. When you will move down the superior part of the bottle, you will notice that the propeller will rotate rapidly and the LED is lighting! Explanation: This is an illustration of the principle of any simple electric generator: electromagnetic induction. When the magnetic field is varying, in the wireofthecoilappearanelectriccurrent,whichlightstheLED.The propeller rotates because of the strong jet of air that flows from the cap hole, when the air in the bottle is compressed. Science Experiments on Renewable Energies2013 - 2015 17 EOLIC MOTOR WITH COCA COLA PAPER CUP proposed by Italian Team Therearetwodifferentwayforproducingeolicenergy:fromthe windandfromafluxofairproducedfromthermaleffect.Inthis experiment we will follow the second way. Aims The aim isto produce an eolic motor with poor materials. MATERIALS/ INSTRUMENTS Support of woodPaper cup ( 1 ), or plastic cup Nail ( 1of 25 cm. ) Bulb( 1 )Electric wire Lamp ( 1 ) or natural sun Carton( 1 paper )

Diagram of operation Science Experiments on Renewable Energies2013 - 2015 18 Realization You must put the nail in to the support of wood, after you have to connecttheelectricwirewiththebulbatthegroundofsupport really close to the nail. In the lower side of paper cup you have to do a small pierce and paste in a small metal cup, again in the same side of paper cup you have to do small cut and produce a blade. The blade paper cup must be placed under the nail. Physical effect Whenthebulbconnectedwiththeelectricsocketstart,theair insidethepapercupbecomewarm,theairfluxgoesintheupper side and push the blade before going outside, the paper cup start and producearotationalmotion.Youcanproducethesameeffect utilisingaplasticcupandlikeasourcethesunradiationforto produce an eolic induced motor. SEAWATER DESALINATION WITH SOLAR ENERGYproposed by Turkish Team Waterisessentialtolife.Theoriginandcontinuationof humankindisbasedonwater.Waterisoneofthemostabundant resourcesonearth,coveringthree-fourthsoftheplanetssurface. However, about 97% of the earths water is salt water in the oceans, andatiny3%isfreshwater.Thissmallpercentageoftheearths water,whichsuppliesmostofhumanandanimalneeds,existsin ground water, lakes and rivers.Theonlylargesourcesofwateraretheoceans,which,however, areofhighsalinity.Theworldswaterneedsareincreasing dramatically.Withseawaterdesalination,wecanfindasolutionto the water-shortage problem.Science Experiments on Renewable Energies2013 - 2015 19 However,theseparationofsaltsfromseawaterrequireslarge amounts of energy which, when produced from fossil fuels, can cause harmtotheenvironment.Therefore,thereisaneedtoemploy environmentally-friendlyenergysourcesinordertodesalinate seawaterandtoacceleratethedevelopmentofnewwater production systems from renewable energies. Dealingwiththeclimateprotectiontargetsandstrong environmental concerns, future water desalination around the world, shouldbeincreasinglypoweredbysolar,windandotherclean naturalresources.Suchenvironmentallyfriendlysystemsshouldbe potentiallyavailableateconomiccosts.Wind,solarandother renewabletechnologiesthatusedfordesalinationarerapidly emergingwiththepromiseofeconomicandenvironmentalviability on a large scale.Inthisexperiment,wewillseeasimplesystemusedtoconvert seawater into fresh water suitable for human use via solar energy. The purpose of a desalination system is to clean or purify seawater andsupplywaterwithtotaldissolvedsolidswithinthepermissible limit of 500 ppm or less. This is accomplished by several desalination methods. Desalinationprocessesrequiresignificantquantitiesofenergyto achieve separation of salts from seawater. This is highly significant as it is a recurrent cost, which few of the water-short areas of the world can afford.ManycountriesintheMiddleEast,becauseofoilincome,have enoughMoneytoinvestinandrundesalinationequipment.The dramaticincreaseofdesalinatedwatersupplywillcreateaseriesof Science Experiments on Renewable Energies2013 - 2015 20 problems,themostsignificantofwhicharethoserelatedtoenergy consumption and environmental pollution caused by the use of fossil fuels.Givencurrent understandingofthegreenhouseeffectand the importance of CO2 levels, this use of fossil fuels is debatable.Solardesalinationisusedbynaturetoproducerain,whichisthe mainsourceoffreshwatersupply.Solarradiationfallingonthe surface of the sea is absorbed as heat and causes evaporation of the water.Thevapourrisesabovethesurfaceandismovedbywinds. Whenthisvapourcoolsdowntoitsdewpoint,condensationoccurs andfreshwaterprecipitatesasrain.Allavailableman-made distillationsystemsaresmall-scaleduplicationsofthisnatural process. Inourexperiment,wewillpresentasolarenergydesalination system. Abasicprincipleofobtainingfreshwaterbysolarenergyis distilled seawater using solar energy. The most advantageous aspect ofthismethodofwatertreatment,noenergyconsumptionis required other than the sun. Materials for this experiment: Cake mold,A small bowl to put in the middle,Science Experiments on Renewable Energies2013 - 2015 21 Coin / ice,BandStretch film. Ourschemeisas follows: Sunlightwillenter throughthetransparent coversofthecontainer deckingandthusheats thewater.Evaporated watercondensedandfilteredonthetransparentcover.Accumulatedwaterisdistilledwaterandusedappropriatelytaken out. In this experiment, we have obtained up to 1.5 litters of drinking water per day. Such embodiments, one square meter of area, per day up to 5.5 litters volume of distilled water can be obtained. THE WARMTH OF THE EARTH proposed by Dutch Team Thedeeperwepenetrateintotheearth,thehigherthe temperature is. This warmth also warms the water stored deep in the earth. Could we use this warmth? Science Experiments on Renewable Energies2013 - 2015 22 What do you need? 1 bottle of glass with a wide opening 1 box of a (oldfashioned) film Dark ink Knitting needle 1 elastic band Experiment Dotwodifferentwatermasseswithdifferenttemperaturesmix immediately if they get in contact? Removethelidofthefilmbox.Turntheelasticbandalrond the opening, like in the drawing. Fill the bottle with cold water. Filltheboxwithwarmwater.Add10dropsofinkintothe warmwaterandstiritwiththeneedle.Sticktheneedle behind the elastic band to fasten it to the box.Holdthe needleatthe topand bring theboxcarefully to the bottom of the bottle. Explanation The warm water out of the box, rises in clouds to the surface. The warmwaterneedsmoreroomthancoldwater,orinotherwords, thewarmwaterweighslessthancoldwaterandthatswhyitlooks as if warm water floats on cold water. Science Experiments on Renewable Energies2013 - 2015 23 Use Bymeansofusingthisprinciple,geothermalusesthewarmthof the earth what is in the water layers underground. The groundwater iscollectedbytwodrillings.Thewaterisdrilledtothesurface,the warmth of the water is being used and then pumped back under the ground again. Twowaysofthermalenergy generation exist; The low energetic wayuseslayersintheearthwith a temperaturebetween30and100 degreesCelsius,whichare1500to 200meterdeep.Weknowseveral uses: heating of cities, greenhouses andSpas.Highenergetic geothermalenergyisproducedby means of geothermic steam. In fact a third way exists, the very low energetic geothermy, which getsthewarmthoutoftheearthfromveryundeeplayersofthe earth with the help of pumps (to a depth less than 200 meters). This is often used in private houses. HOW TO MAKE A WATER TURBINE proposed by Lithuanian Team Use2literplasticbottle.Cuttheplasticbottleintothreepieces. Cut the middle section into 8 pieces (blades). Cut out a side section at the base of the bottle toallow water to flow through it. Then take a cork.Cut8equallyspacedslitsinthecork.Inserttheplasticstrips (blades) into the slits in the cork. Science Experiments on Renewable Energies2013 - 2015 24 Make sure all the plastic strips (blades) curve into same direction around the cork. Then take a pricker. Cut it through the center of the cork (turbine). Remove the pricker and pierce two holes on opposites sides of the bottle.Pushtheprickerthroughoneoftheholesinthebaseofthe bottle.Threadthecorkturbinebackontothepricker.Pushthe pricker through the hole on the other side of the base. Take a string and a weight. Tie it on the pricker.The force of the falling water lifted the weight! Science Experiments on Renewable Energies2013 - 2015 25

PARABOLIC CONCENTRATOR proposed by French Team I. Pattern of a light ray Light travels in straight lines until reflected or scattered by objects in its path. II. What happens when light rays encountera parabolic mirror? Lightraysarealmost parallel.Whenthey encountertheparabolic mirror,theyare concentratedtoonepoint called the focus. III. Why is it useful? Allthesolarenergycarriedbythelightraysareconcentratedin onepoint.So,wecanusethisamountofenergy.Whenputtinga piece of paper on the focus point, it burns immediately. This solar energy can be used to warm up water or food into containers. For example, we can boil water.Therefore, we can build a solar cooker and test it. Science Experiments on Renewable Energies2013 - 2015 26 IV. How to buid a solar cooker We can build a solar cooker using anoldsatellitedish.Ithasa parabolicform.Thenwecancover the surface with mirror film. We have to build a wood structure to fix the satellite dish. Then, we have to place a pan at the focus point. The pan can be filled with water or food. Science Experiments on Renewable Energies2013 - 2015 27 HOW TO MAKE A HOVERCRAFT proposed by Romanian and Turkish team For this experiment we will need: An old CD or DVD disc. A 9 balloon. A pop-top cap from a liquid soap bottle or a water bottle. A hot glue. Steps: 1.Usingapushpin,poke2holesnearthecenterofaclosedsports bottlecap.Makesurethatthetamper-proofringisremovedfrom thecapandthattheholesgoallthewaythroughtheplasticofthe cap. 2.Usethehotglueguntogluethebottomofthecaptothetopof thecompactdisc.Useaslittlehotglueaspossible,butbesurethat thereisaperfectairtightsealbetweenthecapandCD.Givingthe cap a slight twist when you glue it to the CD can help. 3.For better standing up of the balloon, create a collar for the cap by curvingorbendingapieceofcardstockorthincardboard(2"x6"). Cut two slits, one on each end of the card stock that are 1" from the end. Cut the slits on opposite sides of the collar (think of it as the top and bottom of the collar). Join the slits together to create the collar. 4.Find a clean, smooth surface to place the hovercraft on. 5.Inflate the balloon and twist the opening shut. 6.Pull the open end of the balloon through the collar. 7.Stretch the balloon's opening over the sports bottle cap. Science Experiments on Renewable Energies2013 - 2015 28 8.Without letting any air out, place the cardboard collar around the base of the balloon and cap. 9.Now let the air out of the balloon. 10.If the hovercraft doesn't slide or spin easily, make sure the CD isn'twarped.Ifitis,you'llneedtorebuildyourhovercraft.If everything looks normal, try poking larger or more holes in the sports bottle cap. Hovercraftsworkbyusingairtoliftavehicleoffoftheground. TheCDHovercraftisnoexception.Astheballoondeflates,itis releasingairthroughthesportsbottlecapandbeneaththeCD. Because of the shape, smoothness, and weight distribution of the CD, thereleasingaircreatesacushionofairbetweentheCDandthe surface.Thiscushionof airreducesthefriction betweentheCDand surface and allows your hovercraft to move more freely. MINI HYDRO POWER proposed by Italian team Aims Theaimofthisexperimentisevaluatehowmanyenergyit's possible to produce from the mini hydro power blade placed inside a tube.InItalyeachpersonutilize150lofwaterforday,agreat Science Experiments on Renewable Energies2013 - 2015 29 amountofkineticenergycouldbetransformedinelectricalenergy from drain of sinks. MaterialsInstruments Sink( 1 )Voltmeter (1) Blade ( 1 ) Silicone sealant ( 1 ) Tube ( 1 ) Realisation Dates Potential energy=Ep Ep =mgh m = mass of water g = gravitational acceleration h = medium height of column of water In the Betz limit only 0.66 of the kinetic energy can be converted in energy rotation of the blade. Experimentaldatessaythatthepotentialenergyofthewaterin thesinkismorethan0.66electricalenergymeasuredinthe voltmeter. Science Experiments on Renewable Energies2013 - 2015 30 LIVING ON AIR proposed by Dutch team ForagestheDutchhavewindmillsandweusethewindtowork forus.Weusedthemillsforgrindingofgraintobakebreadand becauseweliveundersealevel,forpumpingwateroutofthe countrytokeepdryfeet.Nowadaysweusewindmillstogenerate electricity. This is an applied experiment based on the use of a dynamo. To make it simple keep in mind that: Wecancompareawindmilltoadynamoofabicyclebutitisa wholelotbigger.Thedynamointhewindturbineiscalleda generatorandtheturningiscausedbythewindwhichrotatesthe blades. Now we will tell you the working more specifically: First of all, the wings of the windmills are always put into the right wind direction. Thewingsareonthemainaxiswhichdrivesthegearboxofthe windmill. Thegearboxisbeingoperatedbyacomputersotheexact deceleration can be fixed. Behind the gearbox is the generator which isastrongmagnetandthereisacoil.Themagnetturnsbythe movementoftheaxisandalternatesthenegativeandthepositive poles. So there is a constantly change from north pole to south pole. The magnet turns all the time and because of the constant change of themagneticfield,fromnorthpoletosouthpole,electricityis generatedinthecoil.Thesystemasyouseehere,isbuiltin,inthe helixshapedmodel(seebelow).Atthebackyouseethegenerator Science Experiments on Renewable Energies2013 - 2015 31 withthepermanentmagnetsandcoilwhichgenerateelectricity when the wings turn. a dynamo in a windmill This is how we obtain a electric current called: alternating current. Thisalternatingcurrentistransformedintodirectcurrentbythe generatorandturnedintotherightalternatingcurrent,compatible with the local electricity system. A diagram form of a helix shaped windmill Science Experiments on Renewable Energies2013 - 2015 32 Atschoolwehaveimitatedahelixshapedmodelonour3D printer.Thewindissuckedintothetwist,themodelrotatesmore easily so the windmill generates more energy than one with wings. This model is called Archimedes and will cost less to build and can beplacedonroofsofbuildingsbecausetheyonlyweigha100kilos and make no noise. At school we have made this scale model on our 3D printer. COCA COLA & MENTOS POWER proposed by Lithuanian team

For this experiment you will need: Coca Cola Mentos candiesWater Forms for ice pieces Glass Science Experiments on Renewable Energies2013 - 2015 33 How to produce: To the forms for ice put Mentoscandies. Later forms we fill with water,topourthecandies.Afterputinafreezeruntilcongeal. Frozenicepiecesputinaglassandpourwithcola.Thenbringthis cocktailtoyourboyfriendwehaveafewminutes,whileice piecesmeltandMentosreactwithcolaandstarteruptfromthe glass. It remains to watch a guys reaction. Explanation: Afteralotofdebates,scientistsarenowsayingthattheprimary cause of Coke & Mentos geysers is a physical reaction, not a chemical reaction. Their explanation is this process called nucleation. All the carbon dioxide in the soda all that fizz is squeezed into theliquidandlookingforawayout.Itsdrawntoanytinybumps thatitcangrabonto.Thosetinybumpsarecallednucleationsites: places the gas can grab onto and start forming bubbles. Nucleationsitescanbescratchesonaglass,theridgesofyour finger, or even specks of dust anywhere that there is a high surface area in a very small volume. The surface of a Mentos is sprayed with over 40 microscopic layers ofliquidsugar.Thatmakesitnotonlysweetbutalsocoveredwith lots and lots of nucleation sites. In other words, there are so many microscopic nooks and crannies on the surface of a Mentos that an incredible number of bubbles will form around the Mentos when you drop it into a bottle of soda. SincetheMentosarealsoheavyenoughtosink,theyreactwith the soda all the way to the bottom. The escaping bubbles quickly turn into a raging foam, and the pressure builds dramatically. Allthat pressurehasgottogosomewhere,and beforeyouknow it, you've got a big geyser happening! Science Experiments on Renewable Energies2013 - 2015 34 BUILD A WINDMILL! proposed by French team Components needed: A piece of cork, a motor,two wires, a Led, a sheet of thick paper, a needle and a hair dryer Build the blades: Draw a 15 cm square on the paper. Cut it up. Draw 2 diagonals. Cut upandfoldtoformtheblades,asitisshownonthefollowing pictures: Fix the blades on the cork thanks to the needle: Put the axis of the motor in the cork. Use the windmill: Plugthewiresand the Led in the motor. Testthismodelwith the hair dryer. Lookatthewindmill turningandtheLed lightning! Science Experiments on Renewable Energies2013 - 2015 35 HOW TO MAKE A WIND TURBINE proposed by Romanian team Simply stated, a wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity.Thegeneratorcanproduceelectriccurrenttowards electromagneticinduction(orsometimesjust induction),whichisa processwhereaconductor placedinachangingmagneticfield(or a conductormovingthroughastationarymagneticfield)causesthe production of a voltage across the conductor.Inthisexperimentweuseachangingmagneticfieldobtained through the rotation of an ax with small but strong magnets glued on themiddleofit.Aboveandbelowthemovingaxthereare2home-made coils, from copper wire which are connected to a LED. Building a model of a wind turbine can be done by using only parts of scrap materials: plastic fan blade, metallic supports and ax, plastic supportsfor making2coils, copperwirefor coils,small partsofstrong magnets,some metallicscrews,1 LED. Science Experiments on Renewable Energies2013 - 2015 36 As showed in the picture, we build a structure for supporting the 2 coils, allowing the moving of the ax between them. When the blades arerotating,themovementistransmittedtotheaxthroughadisc with a rubber band and so the magnetic field is changing and electric current is produced, making the LED to light as long as the blades are rotating. HOMOPOLAR MOTOR proposed by Italian team Ahomopolarmotorisadirectcurrentelectricmotorwithtwo magneticpolestheconductorsofwhichalwayscutunidirectional lines ofmagnetic flux by rotating a conductor around a fixed axis that isparalleltothemagneticfield.TheresultingElectromotiveForce beingcontinuousinonedirection,thehomopolarmotorneedsno commutatorbutstillrequiresslipringsThenamehomopolar indicatesthattheelectricalpolarityoftheconductorandthe magneticfieldpolesdonotchange(i.e.,thatitdoesnotrequire commutation). Science Experiments on Renewable Energies2013 - 2015 37 History: The homopolar motor was the first electrical motor to be built. Its operationwasdemonstrated byMichael Faraday in 1821 at theRoyalInstitutionin London. In1821,soonafterthe Danishphysicistandchemist HansChristianOerstad discoveredthephenomenon ofelectromagnetism,Humpry DavisandBritishscientistWilliamHydeWollastromtried,butfailed, todesignanelectricmotorFaraday,havingdiscussedtheproblem with the two men, went on to build two devices to produce what he called"electromagneticrotation".Oneofthese,nowknownasthe homopolarmotor,causedacontinuouscircularmotionthatwas engenderedbythecircularmagneticforcearoundawirethat extendedintoa poolof mercurywhereinwasplacedamagnet. The wirewouldthenrotatearoundthemagnetifsuppliedwithcurrent fromachemicalbattery.Theseexperimentsandinventionsformed thefoundationofmodernelectromagnetictechnology.Inhis excitement,Faradaypublishedresultswithoutacknowledginghis work with either Wollaston or Davy. The resulting controversy within the Royal Society strained his mentor relationship with Davy and may wellhavecontributedtoFaradaysassignmenttootheractivities, whichconsequentlypreventedhisinvolvementinelectromagnetic research, for several years. B.G.Lammedescribedin1912ahomopolarmachinerated2,000 kW,260V,7,700Aand1,200rpmwith16slipringsoperatingata peripheralvelocityof67m/s.Aunipolargeneratorrated1,125kW, Science Experiments on Renewable Energies2013 - 2015 38 7.5V150,000A,514rpmbuiltin1934wasinstalledinaU.S.steel mill for pipe welding purposes. Principle of operation ThehomopolarmotorisdrivenbytheLorentzForce:asitmoves throughamagneticfield,theconductorispushedthrougha magnetic field by opposing forces. This force induces a torque around theaxisofrotation.Becausetheaxisofrotationisparalleltothe magneticfield,andtheopposingmagneticfieldsdonotchange polarity,nocommutationisrequiredfortheconductortokeep turning.Thissimplicityisachievedatthecostofnotbeingableto havemorethanonecoilturn,whichmakesthisconfigured homopolarmotorunsuitedformostusefulapplications.Homopolar motorshaveadvantagesanddisadvantagesandhavenotbeenfully developed. Likemostelectro-mechanicalmachines,ahomopolarmotoris reversible:iftheconductoristurnedmechanically,thenitwill operate as a homopolar generator, producing a direct current voltage betweenthetwoterminalsoftheconductor.Thedirectcurrent produced is an effect of the homopolar nature of the design. Building a simple homopolar motor Ahomopolarmotorisveryeasytobuild.Apermanentmagnetis usedtoprovidetheexternalmagneticfieldinwhichtheconductor willturn,andabatterycausesacurrenttoflowalongaconducting wire.Itisnotnecessaryforthemagnettomove,oreventobein contactwiththerestofthemotor;itssolepurposeistoprovidea magneticfieldthatwillinteractwiththemagneticfieldinducedby the current in the wire. One can attach the magnet to the battery and allowtheconductingwiretorotatefreelywhileclosingtheelectric circuitbytouchingboththetopofthebatteryandthemagnet Science Experiments on Renewable Energies2013 - 2015 39 attached to the bottom of the battery. The wire and the battery may become hot if operated continuously. Ahomopolarmotorisveryeasytobuild.Apermanentmagnetis usedtoprovidetheexternalmagneticfieldinwhichtheconductor willturn,andabatterycausesacurrenttoflowalongaconducting wire.Itisnotnecessaryforthemagnettomove,oreventobein contactwiththerestofthemotor;itssolepurposeistoprovidea magneticfieldthatwillinteractwiththemagneticfieldinducedby the current in the wire. One can attach the magnet to the battery and allowtheconductingwiretorotatefreelywhileclosingtheelectric circuitbytouchingboththetopofthebatteryandthemagnet attached to the bottom of the battery. The wire and the battery may become hot if operated continuously. CHEMICAL ENERGY & SODA ROCKET proposed by Turkish team In the experiment, we will see just how explosive and exciting the combination of baking soda and vinegar can be when it is in the right setting. Science Experiments on Renewable Energies2013 - 2015 40 Materials A plastic bottle Glue Styrofoam Aluminum Folio VinegarBaking soda Paper towel Rubber Stopper Procedure 1.OurRocketneedstohaveasteady launchplatform.WeusedStyrofoamto make 3 wings at the bottom of the bottle. 2. WecoveredthebottlewithAluminum Folio to decorate the rockets. 3.Wewillfillthehalfofthebottlewith white vinegar. 4.(Tear off about 1/4 of the paper towel and put one tablespoon of baking soda on the piece of paper towel.) 5.Wewillwrapthebakingsodainthe piece of paper towel.6.(This step has to happen quickly, or what you will have is a failure to launch.)7.Wewillputthebakingsodainsidethe bottleandimmediatelyputtherubber stopperintotheopeningofthebottle.We Science Experiments on Renewable Energies2013 - 2015 41 will shake the rocket quickly, hardly and set it. 8.Stand back! How does it work?What do you see when you mix baking soda with vinegar? You see alotofbubbling.Thebubblesthatyouseeareactuallybubblesof carbon dioxide gas being released through an acid and base reaction. Vinegar contains acetic acid (the reason it tastes so sour), and baking sodacontainssodiumbicarbonate(abase).Theirreactionmakes carbonic acid, an unstable acid that quickly breaks down into carbon dioxideandwater.Thecarbondioxidethenrapidlybubblesoutof the water. Whenyouclosethebottlewiththerubberstopper,youprevent thegasesfromescapingthebottle,butyouareincreasingthe amountofgasesinsidethebottlebycreatingcarbondioxide.The introductionofcarbondioxideinsidethebottlecausesarapid increase in air pressure inside the bottle. The air pressure eventually getstothepointthattherubberstoppercannolongercontainthe gasesitholdsinsidethebottleandWHOOOOOOSH!...thestopper and the contents of the bottle rush downward.Asthecontentsofthebottlerushdownward,thebottleitself shootsupward.Howdoesthathappen?Thisisafundamental demonstrationofNewton's ThirdLawofMotion:forevery action,thereisanequaland oppositereaction.Theinitial action is the rush of matter and forcedownwardfromthe bottle'sopening.Thereaction is the bottle jettisoning upward. Science Experiments on Renewable Energies2013 - 2015 42 RENEWABLEENERGY FROM TAKING A SHOWER proposed by Dutch team Withthefollowinguseinpracticewewouldliketoshowandto prove that metal is an excellent heat conductor. Totakeashowerwateris heatedupfromabout10to about 40 degrees Celsius. Thiscostsquitesome energy. Aftertakingashowerthe used water disappears into the sewerage system. It is possible though,towinthewarmthof the shower water by means of aheatexchangeinthedrain tube.Thewaterinthecentral heating boiler can get up to 20 to 25 degrees in this way. Now youneedlessenergytowarm the water up to 40 degrees the next time you take a shower or need hot water. How does it work: Imagineyoutakeashower. Thewaterrunsintothedrain pipewhichconsistsoftwo copperpipes.Copperisavery Science Experiments on Renewable Energies2013 - 2015 43 good heat conductor. Through the inner copper pipe the used warm waterrunsanditwillgiveitswarmthtothecopperpipebeforeit ends up in the sewerage system.Thecoldwatercomingfrom thewatersupplyconnection, goingtothecentralheating boiler,runsbetweenthetwo copper pipes. This cold water(10 degrees)runsalongthewarm copper pipe and consequently the temperatureintheboilerwillrise up to 27 degrees. You can imagine thatheatingwaterfrom27 degreesto40degreescostsless energy.Thelengthofthepipeis of great influence on the output. Thelongerthepipethemore theeffect.Iftheshowerisonthesecondfloor,likeinmanyDutch houses, and the copper pipes could be 180 cm, it is possible to get a saving of 50%. In this way you save a lot of energy! Science Experiments on Renewable Energies2013 - 2015 44