I love all the alternative energy projects that are around here, I especially like the solar air heater. So I figure that I might be able to get some input on a problem I face.
There is a program called Merit Badge University at Carnegie Mellon University that I'm helping with. Basically over five hundred boyscouts come for merit badge classes in stuff they normally wouldn't be able to get with just their troop such as Chemistry, Computers, Architecture, and Citizenship of the World. I'm stepping in at the last minute to teach the merit badge in Energy after a bunch of cancellations and I need help thinking up projects boyscouts could do in a few hours (2-3) that could help drive home some lessons in energy. I've already taught the first half of the class a weekend ago and I've done about as much lecturing as they can take. They've already had the chance to do homework at home looking at ways they consume energy and I even had them make Rube Goldberg devices to teach them about kinetic and potential energy and energy transfers. They now know all the different types of energy; chemical, electrical, kinetic, etc.

So now I need to find a way to keep them busy for another three hours this weekend. I've found some cool things.

http://perso.orange.fr/ballonsolaire/en-index.htm

and some classic things,

http://solarcooking.org/plans/

and some things I could do in a limited time

http://www.fuelcells.org/ced/career/scienceproject.pdf

and some that are cool but take WAY to much time

http://www.re-energy.ca/pdf/biogas-generator.pdf

Also it's supposed to rain on saturday here in pittsburgh so my plans for anything solar or outdoors may be soaked. So if you can think of a good project that I could do with the scouts please reply. It needs to be short enough that they can come in and build or do the experiments in only a few hours and it needs to use fairly simple components ( I can get a hold of things like multimeters or various harmless chemicals if I need them). So simply let me know if you know of something that will hold their interest.

Hi,
Just some quick ideas for a rainy day....
Energy and Ecosystems--somewhat safe easy to do experiments. Students collect plants after instruction. Gather parts of soft green plants like weeds and grass. (Get permission to pick them and show how not to uproot valuable plants like grass.) Have students tear up items into smaller pieces into test tubes and then pour in rubbing alcohol. The chlorophyll will be extracted from the plant. Get it started in the morning and then you can work on other experiments. Chlorophyll captures solar energy and changes it into chemical energy. It is the key to almost all life on earth. Give safety rules regarding alcohol and if they don't have goggles you can pour the alcohol at your desk and then place the test tubes to the side of the room for later observation. In 2 hours you should see some green developing but it gets darker with time. You can try first to see if it meets your time requirements. Part 2--the role of CO2 the plant makes sugar with the carbon dioxide and the water and the energy from the sunlight. They can see CO2 in their respiration by bubbling their breath out into water in cups and then testing with a ph strip before and after. This one is a bit hard since it depends on the water and there is not a big change in the color of the strips, but it does work if done right. They have to blow into the water for a while. They make a weak acid with the CO2. Part 3--Show Carbon Dioxide Gas. Have them pour vinagar into a pitcher on top of some baking soda. Then you can carefully pour the gas out of the pitcher. Have a lit candle in a glass baby food jar. Don't let the liquid pour out just the gas. The candle will be extinguished and the act of pouring something invisible is a bit neat. (make sure a lit candle is ok in the room and is closely supervised. Some rooms have sensitive smoke alarms and even a bit can set them off.) You could do some other experiments with the stored starches in plants.... there are some cool ones out there and you are done. Knowlege level can be scaled as well. There are whole college courses on photosynthesis and energy transfer and storage in plants. Mix these in with a few more and you have a collection to fill your day. It should provide lots of hands-on chemistry experience.

If you go for a solar project, there are simple insulated box ovens they could make. I'd stay away from concentrating collectors since they won't work at all with clouds. Plus, the bright light can harm unsheilded eyes. Under some sun a black solar oven should get warm... but I don't know if it would bake chocolate chip cookies. Kids do that here for their science fair projects. Great knowledge yelding good rewards.
Good luck,

If it is going to be a nice damp day, static electricity experiments should keep them involved and entertained zapping each other. Then you could bring up Tesla if you're feeling brave.

Another good one is making a potato battery like here.....Potato Power and lighting up an LED with it.

One of my favorites for kinetic energy is gyroscopes. Lotta fun.

Peltier modules are pretty cool, like the ones used in portable battery-powered coolers. The interesting thing about them is if you apply heat on one side (concentrated sunlight?) and cold to the other (water cooling?) you get electricity out depending on the temperature differential. Can't do that with a regular air conditioner.

Tgreenwood

If you have an Old diesel car sitting around, convert it to Bio-fuel. We are working on one at our school. Goto www.lovecraftbiofuels.com for parts and info. Basically you can make the car run on vegitable oil. Our car currently has Soy oil in it.

Oh, and use a Van digraph generator instead of a telsacoil for tgreenwood's suggestion. Does not hurt as much.

How did it work out? What did you end up doing with the kids?
Thanks,

Well it could have been better. It was a rainy cloudy day which blew all my plans with solar, wind, or anything outside. So instead I did a lesson around fuel cells where they did an experiment electrolyzing water and measuring the changes with a voltometer. I also did some demonstrations with a pielter heat pump and taught them about biofuel and microbial fuel cells. Then they were bored so I filled the last half hour with an abridged version of the free energy episode of mythbusters (yeah yeah a copout). In the future there will hopefully be nicer weather and more to do but for a first time seat of the pants venture this went fairly well. Thank you to everyone for suggestions.

The Lowest power consumition for proyector DIY based on LCDs panel will be using a source of light composed by some RGB leds. Note that R, G and B leds don´t emit the same amount of light.

You should to build an half sphere and dispose the leds (total stimated about 6000) at concave side (inside) everyone spoting to the same point. This point will be your virtual white light lamp bulb.
.... _
.../
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l .......O
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...\_

Then continues building you proyector normaly as other DIY LCD proyectors.
The Sphere is the key to keep light controlled, to use thousans of leds as one, every cones of light must point the same place, and every led has to be at the same distance from that point (virtual bulb).

Other solution is using buying a fresnel composed by thusans of microfresnels to colimate light from every led but this may result too expensive, except if you desing it, produces and sell every us at world, making a DIY revolution and killing ballast and that uneffective unefficient unecological HQI bulb lamps.

Tian has made an led proyector, with less than 1000 white leds without coliameting light. Apart white leds emit near no red light (see my 19´´Stereo3DHDTV page 5) and the result is a photo of a proyected image where the proyector doesn´t appear and a laptop result dimmer than proyected image. That photo seem to be made from a comercial DLP proyector not a super ecological and superdimmer DIYLEDPj. If I had a superbright led projetor I will show everybody to avoid 400w projectors which emit UV, IR, and an emoreous amount of unusefull light (we only use RGB from all spectal wacthable, the rest is blocked, filtered by RGB pigments of the LCD panel).

Thanks, I was wondering. Pielter devices are neat. My folks have a pielter powered fan on top of their wood burning stove. The heat from the stove is changed into dc power, and a fan blows hot air across the room. It slows down when the fire cools, so it acts as a visual gauge telling us when to add more wood. I thought the heat would kill it, and it would not last. It has been going strong for several years now.
I've heard about the microbial fuel cells on the radio. A scientist somewhere has bacteria that live in muck that generate electric current. It seems almost unreal but when habitats are connected together they can crank out enough power to run LED lights.
Fuel cells are magical too. Personally, I wish some forgotten WWII tecnology could be brought back to help fuel cells get power from biological sources. (I remember reading that Germans had special retorts that produced hydrogen/carbon rich off gas from wood.) I think it would be a great blending off new and old technology. It's been a while since I saw the formulas, but from memory the WWII gas looked like what some fuel cells use today.
Sorry, the weather kept the solar projects from happening. Science Rules.