This giveaway is now closed. Thanks for stopping by. The winner is Chrysa. Congrats!
I recently participated in an online briefing with Dave Lettero and Heidi Eggert from the Bonneville Environmental Foundation (BEF), and several prominent bloggers to discuss how we can all reduce our carbon footprint. Traditionally, fossil fuel is how we obtain most of the energy in our country but BEF is working to change that by helping companies become better environmental stewards. The highlight of the briefing was learning how to create a solar oven and a solar cell. Both of these activities can be completed by children (with adult assistance and supervision). The solar oven project is geared towards younger children, while the solar cell project is geared towards older children. I have included both activities below in case you’d like to try them out with your children:
Activity: Solar Oven
OVERVIEW: This is a two-part activity. In Part I students work with the Sun Oven to cook food and purify water using solar energy. In Part II students make their own solar ovens using common household materials.
GOAL: Students learn the basic principles of solar-thermal and passive-solar heating.
TIME FOR PART I: 30 minutes to 1 hour
TIME FOR PART II: 2-3 1-hour class periods
SETTInG FOR PART I: Outside on a sunny day.
SETTInG FOR PART II: Classroom for oven construction and outside on a sunny day for testing ovens and cooking.
MATERIALS FOR PART I: The Sun Oven and Sun Oven manual are in your science kit. You’ll also need a pot to hold water, water, and food to warm up in the oven (e.g., 1-2 student lunches).
MATERIALS FOR PART II: Pizza boxes, tin foil, clear plastic wrap, tape, black construction paper, a stick (for propping the oven open), thermometer, and food to cook in the oven (e.g., bread with cheese).Solar Oven Instructions
PART I: Use the Sun Oven and the Sun Oven manual to cook food and pasteurize water in the oven. The oven has a built-in temperature gauge so the process can be monitored.
PART II: Construct homemade solar ovens. Depending on class size, students can work in groups of three to five.
1. Use a box knife or sharp scissors to cut a flap in the lid of the pizza box. Cut along three sides, leaving about an inch between the sides of the flap and the edges of the lid. Fold the flap out so that it stands up when the box lid is closed. Cover the inner side of the flap with aluminum foil so that the rays from the sun will be reflected off.
2. Use clear plastic wrap to create an airtight window for sunlight to enter into the box. Do this by opening the box and taping a double layer of plastic wrap over the opening you made when you cut the flap in the lid. Leave about an inch of plastic overlap around the sides and tape each side down securely, sealing out air.
3. Line the bottom of the box with aluminum foil to reflect heat and then cover that with black construction paper (black absorbs heat).
4. Now your oven is ready to try out! Take it outside to a sunny spot and adjust the flap until the most sunlight possible is reflecting off the aluminum foil and onto the plastic-covered window. Use a stick or a dowel to prop the flap at the right angle.
Pizza-box solar ovens will reach about 200 °C on a sunny day, so they take longer to heat things up than a conventional oven does. Try melting mozzarella cheese over toast with basil and tomatoes, warming leftovers for lunch, or experimenting with any other food you can think of ideas for.To build a more advanced homemade oven, visit the Solar Cooking Archives online (http://solarcooking.org/).
Activity: Create a Solar Cell
OVERVIEW: In this two-part demonstration, a sheet of copper flashing is transformed into a semiconductor to demonstrate the photovoltaic principle.
GOAL: Students learn that semiconductors can be used to generate current and are introduced to the photovoltaic principle.
TIME FoR PART I: 1 hour to cooker copper flashing and 20 minutes for the flashing to cool
TIME FoR PART II: 30 minutes for class demonstration and discussion
The steps can take place during two class periods, or Part I could be done before class.
SETTInG FoR PART I: Kitchen or science lab with a burner to cook copper flashing.
SETTInG FoR PART I: Outside on a sunny day to perform demonstration.
MATERIALS FoR PART I: 2 pieces of 4 x 4 copper flashing (in science kit), scissors, sandpaper or wire brush, mental tongs, and a stove or single burner.
MATERIALS FoR PART II: Plastic container (3-liter bottle with the top cut off), multimeter (in science kit), alligator clips, and saltwater.Create a Solar Cell
Background:
The cuprous oxide created during the cooking process turns an ordinary piece of copper into a type of material called a semiconductor. A semiconductor is in between a conductor and an insulator. In a conductor electricity can flow freely. In an insulator electrons are bound tightly to their atoms and do not flow freely. In a semiconductor there is a gap (called a bandgap) between the electrons that are bound tightly to the atom and the electrons that are farther from the atom which can move freely and conduct electricity. Electrons cannot stay inside the bandgap. An electron cannot gain just a little bit of energy and move away from the atom’s nucleus into the bandgap. An electron must gain enough energy to move farther away from the nucleus, outside of the bandgap. Similarly, an electron outside the bandgap cannot lose a little bit of energy and fall just a little bit closer to the nucleus. It must lose enough energy to fall past the bandgap into the area where electrons are allowed.
When sunlight hits the electrons in the cuprous oxide, some of the electrons gain enough energy from the sunlight to jump past the bandgap and become free to conduct electricity. The free electrons move into the saltwater, then into the clean copper plate, into the wire, through the meter, and back to the cuprous oxide plate.
To Create a Solar Cell:
1. Prepare the Copper: Wash your hands so they don’t have any grease or oil on them. Use metal sheers or strong scissors to cut a piece of the copper sheeting roughly 6 x 6 inches, about the size of the small burner on a stove. Then wash the copper sheet with soap or cleanser to get any oil or grease off of it. Use sandpaper or wire brush to thoroughly clean the copper sheeting so that any sulfide or other light corrosion is removed.
2. Turn Copper into Cuprous oxide: Place the cleaned and dried copper sheet on the burner and turn the burner to its highest setting. As the copper starts to heat up, oxidation patterns will begin to form. Oranges, purples, and reds will begin to cover the copper sheeting. As the copper gets hotter, the colors are replaced
with a black coating of cupric oxide. This is not the oxide we want, but it will flake off later, showing the
reds, oranges, pinks, and purples of the cuprous oxide layer underneath. The last bits of color disappear as the burner starts to glow red. When the burner is glowing red-hot, the sheet of copper will be coated with a black cupric oxide coat. Let it cook for a half hour until the black coating is thick. This is important because a thick coating will flake off nicely, while a thin coat will stay stuck to the copper. Use tongs to remove the copper sheet form the heat and place it in a sink to cool. As the copper sheeting cools, it will shrink. The black cupric oxide now covering the surface also shrinks, but at a different rate than the copper beneath. Black flakes of cupric oxide will pop off the copper with enough force to make them fly into the air. When the copper has cooled to room temperature (about 20 minutes), most of the black oxide will be gone. Rub the sheet lightly with your hands and run it under water to remove most of the remaining black oxide. You do not need to remove all of the black spots, as doing so might damage the delicate red cuprous oxide layer, which is needed to make
the solar cell function. Carefully bend the two pieces of copper (one that you cooked in Step 2 and one that has not been cooked) and fit them in the plastic container so that they do not touch each other. The cooked copper should have the reddest side facing out towards the sun. Set your multimeter to provide readings in mil-
livolts. When the sun shines on your solar cell, you will begin to generate power. In the photo to the right the solar cell is generating 81.6 millivolts. Notice that if you block the sunlight striking the container the voltage quickly decreases
3. Assemble the Solar Cell: Fill the container with hot tap water so that a top portion of both pieces of copper will remain dry. Mix about two tablespoons of salt into the container, and stir the water until all the salt is dissolved.
4. Monitor the Solar Cell: Connect the cuprous oxide to the positive (red) lead of the multimeter, and connect the clean copper sheet to the negative (black) lead of the meter.
5. Now move your container out of the sun light. Notice that the solar cell still generates an electrical charge even in darker conditions.
If you’d like more information on how to shrink your carbon footprint, check out BEF’s site, Shrink Your Foot. This interactive site has tips/tools on how to reduce your carbon footprint.
Win It! One of you will win a Solar Car Kit. Simply head on over to Shrink Your Foot. Come back here and leave me a comment with something you learned. Comments will close on June 14, 2009 at 10 PM PST. One comment per person, please (unless you do the extra credit). US residents only. Duplicates and comments not including the above information will be disqualified. Comments are moderated. If you don’t see your comment in a reasonable amount of time, send me an email. Bloggers and non-bloggers may enter. If you don’t want to leave your email address, please be sure to check back for my announcement on the winner. Please note that winners must respond within 48 hours of being announced/contacted or another winner will be drawn.
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Marilyn Wons says
Over a lifetime a tree can absorb over a ton of C02!
alma gros says
over its lifetime, one tree can absorb more than a ton of CO2.
PLANT A TREE.
Margaret Smith says
What a really interesting site. About 4% of U.S. energy consumption goes to our T.V. sets. LCD’s use 1/2 the energy of plasma TV’s.
Great prize. This solar car is a wonderful way of teaching kids about solor energy. Thanks so much for this giveaway.
Margaret Smith says
I’m an email subscriber.
Thanks again.
Jaque says
The average U.S. home electricity use produces 16,366 lbs of carbon dioxide a year! We need more trees!!!!
Thank you. 🙂
beth shepherd says
I learned that the Bonneville Environmental Foundation (BEF), a Portland, Oregon-based nonprofit organization, was established in 1998 to further the development and use of new renewable energy resources and restore watershed ecosystem.
Thank you for the chance!
[email protected]
Denyse says
BEF has partnered with leaders in the sports and recreation industry to build support for non-polluting renewable sources of energy by developing carbon offset programs.
Angela J says
You can calculate your carbon footprint.
Monique Rizzo says
Trees absorb a ton of CO2! Thanks for the chance.
[email protected]
Christine V says
can calculate your carbon footprint
bridget says
This is a really cool site for kids. I learned that properly inflating my tires could save me one tank of gas per year.
Janice Wright says
Approximately 90% of your purchase dollars goes directly toward purchasing renewable energy offsets from new renewable energy production facilities across the country. This means that your purchase directly contributes to the addition of clean energy to our nation’s grid.
amir says
My wife saves 700 pounds of CO2 every 6 months from going into the air. We live in FL and she always hangs out our clothes.
dianne says
I learned that properly sealed windows can save energy since the hot or cool air won’t be escaping.
McClure family space says
a tree can absorb a ton of co2!!
McClure family space says
i subscribe
McClure family space says
i have your button!
Sarah says
keeping your tires properly inflated can save one tank of gas a year!
Small Footprints says
What a great site … thanks for telling us about it. I learned that using a low flow shower head can save us 9 gallons of water during a 6 minute shower. Very Cool!
Thanks!
Small Footprints
michael says
it’s interesting how you can figure out your carbon footprint
Roz says
A heavier car burns fuel less efficiently. Interesting. This may be the incentive I needed to clean out the back of the car.
Marianna says
I learned that the average U.S. home electricity use produces 16,366 lbs of carbon dioxide a year.
And that foot reminds me of Monty Python! lol
Tammy N. says
Great website for teachers! I will use it a lot in the future.
I didn’t know that flying from NY to LA creates 2 tons of Co2 per passenger. This makes me wonder how we can still fly, but do other things to offset our carbon footprint. I think I will explore the website some more.
Jennifer C. says
One BEF Carbon Offset represents enough renewable energy to power a typical home for a month with clean wind or solar energy.
Mama Zen says
Cows that eat grass burp less than cows that eat corn!
Sonya says
Adding an extra 100 lb of weight ups your fuel usage by 2%
Sonya says
I’m an email subscriber
Sonya says
I have your button on my blog
Jen M says
LCD tv’s use half the energy that plasmas do.
rachel says
i learned i should check my tire pressure in my car very often
Jennifer M says
It seems that if you feed cows the diet they evolved to eat – grasses – they don’t burp nearly as much as when they eat the usual livestock feed made of things like corn and soy, in fact, 18% less.
Dan Riley says
Over a lifetime a tree can absorb over a ton of C02–I have a dozen dwarf fruit trees–maybe next year I’ll start making apple wine–only in the interest of saving the planet!
Kathy Scott says
a tree can absorb a ton of co2!!
Erma says
I had learned over its lifetime, one tree can absorb more than a ton of CO2.
michelle robbins says
you can calculate your carbon footprint. you can plant a tree to help absorb some of the co2
georgie says
The earth is experiencing climate change!
electricisland(at)gmail.com
georgie says
Subscriber!
Diane Baum says
I learned a lot of things, including inflating my car tires could save me a tank of gas per year.
katie says
I learned the average carbon footprint for my single family home–18,419 pounds of carbon dioxide per year!
katie says
I subscibe via Google Reader 🙂
Beverley Justice says
I learned that using a low flow shower head can save us 9 gallons of water during a 6 minute shower.
Christie says
I learned that one BEF Carbon Offset represents enough renewable energy to offset the greenhouse gas pollution produced by a typical home for a month.
Christine Walker says
I learned that over a lifetime a tree can absorb over a ton of C02.
Christine Walker says
I tweeted and follow on Twitter.
http://twitter.com/nomorecages87/status/2164303076
Christine Walker says
I subscribe via email.
Christine Walker says
I blogged about this giveaway.
http://nomorecages.blogspot.com/2009/06/solar-car-kit-giveaway.html
Christine Walker says
I have your button on my blog.
Christine Walker says
I stumbled this giveaway.
ID: nomorecages
sito says
I learned: BEF Wind and Solar Blend Offset (50% wind energy resources built after 2005 and 50% solar energy resources built after 2005): Represents 1,500 pounds of CO2 not emitted into the atmosphere
sito says
Twitter follower & tweeted, http://twitter.com/sito50/status/2164911385
sito says
E-mail subscriber.
sito says
I have your button, http://sitosfunstuff.blogspot.com/
Kimberly Pruitt says
It was very cool that you can calculate your carbon footprint..and scary to see what effect it has on the environment!
It is an awesome site though, I am going to show it to my teenager.
gloria says
The average U.S. home electricity use produces 16,366 lbs of carbon dioxide a year.
[email protected]
gloria says
http://kngmckellar-glorias.blogspot.com/
I left a blog.
[email protected]
gloria says
I subscribe via email.
[email protected]
gloria says
http://twitter.com/kngmckellar
I follow you on twitter and tweeted
[email protected]
Rozie says
I learned that I need to be using compact fluorescent light bulbs 😉
Kristin says
there is really nothing to speak about….other than enter me to win this contest….no afraid to try anything new
Jessica H says
Over a lifetime a tree can absorb over a ton of C02!
Jessica H says
I subscribe
kathy pease says
1998: BEF was established as a foundation. The Board of Directors included utility CEOs, tribal representatives, a fish biologist, an aluminum plant owner, two environmental advocates; and was chaired by retired U.S. Senator Mark Hatfield.
kathy pease says
http://twitter.com/klp1965/status/2169028401
kathy pease says
subscriber
Tammie says
Here’s a fact that is sure to catch alot of people (myself included) unaware – pound for pound a TRAIN is the most energy-efficient and carbon friendly mode of transportation!
Rickie Johnson says
Over a lifetime a tree can absorb over a ton of C02. So these hundreds of pine trees around mmy house are really doing their part. LOL
Cole Evans says
Properly inflated tires save you approximately one tank of gas a year! That’s good to know.
Randy Bailey says
Over a lifetime 1 tree can absorb more than a ton of CO2
DanV says
I learned that you can buy carbon offsets for home, car or flight, or offset by selecting a specific dollar amount.
Chrysa says
I learned that sealed windows keep heat in during winter and a/c in summer.
Gianna says
Cows that eat grass burp less than cows that eat corn.
Denise says
A low-flow showerhead can save 9 gallons of water per 6 minute-shower is one of the things that I learned. Nice!
Pamela White says
I learned that the average single family home creates over 18,000 lbs of CO2 per year.
Lily Kwan says
I learned that BEF has partnered with leaders in the sports and recreation industry to build support for non-polluting renewable sources of energy by developing carbon offset programs.
Lily Kwan says
I subscribed to your email feed.
Janet says
The average U.S. home electricity use produces 16,366 lbs of carbon dioxide a year! ty 4 the great review, awesome giveaway, and 4 the entry:)