Alternate Energy Sources

wind power

Wind isn't just some uncontrollable part of nature that messes up our hair or sucks up Dorothy, Toto and anything else in its way. It can't be trained but it can be put to work. The kinetic energy of wind can be changed into other forms of energy. When a boat uses a sail to push it, that is one form of wind energy at work. Farmers have been using wind energy for years to pump water from wells and turn large stones to grind wheat or corn - just like a water wheel.

Wind is also used to make electricity. Blowing wind spins the blades on a wind turbine - just like when you blow on a toy pinwheel. When the blades turn, the turbine is operating and electricity is generated. The turbine has a brake, so if the wind blows too hard, the brake can stop the blades from being damaged. Some wind turbines are up to 10 stories high and have blades as long as 50 feet. Wind turbines don't create any pollution but they can be pretty noisy.

Wind has to blow at speeds of 12 to 14 miles per hour to turn the turbines fast enough to create electricity. The turbines usually produce about 50 to 300 kilowatts of electricity each.

http://content.time.com/time/video/player/0,32068,27456914001_1907002,00.html

Activity 1; pros and cons. Watch the video and write down two good things and two bad things about using wind power.

http://video.pbs.org/video/2289327437/

Activity 2:Go to this game site and see if you have what it takes to power a city. Game: http://climatekids.nasa.gov/power-up/

https://www.brainpop.com/science/energy/windenergy/preview.weml

solar power

Solar energy is the energy we acquire from the sun. Millions of years before humans realized the sun's potential as a renewable energy source, plants were using the sun's energy to convert carbon dioxide and water into sugars to eat. This process is called photosynthesis. Today, we have tried to copy plants by creating something called photovoltaic (PV) cells. These man-made cells are comprised of semiconductors, which are materials that are able to absorb light energy. The most commonly used semiconductor today is silicon because it is, so far, the most cost-effective material. The silicon absorbs a portion of the energy from the light that shines down on it, electrons are suddenly knocked free and are channeled to flow in the same direction by electric fields within the PV cell. On both the top and bottom of the silicon, metal contacts are placed and, through these contacts, the solar energy is extracted and stored.

Practical Uses

Solar energy is used for a variety of different things but the ones that you are most familiar with are solar-powered calculators, solar-heated swimming pools and maybe even the hot water in your house is heated by solar panels. Because solar energy is clean and renewable, it would be ideal to make a move from non-renewable heating sources like gas to solar on a grander scale, so research is ongoing to make solar energy a more cost-effective alternative for people around the world. Enough sunlight falls to Earth every hour to meet the world's energy demands for an entire year - the trick is learning how to extract that energy in a cost-effective way.

https://www.brainpop.com/technology/energytechnology/solarenergy/preview.weml

hydroelectric

It's hard to imagine that water can be used to create electricity. The two are a dangerous combination that should never mix, right. True, so never bring your stereo in the shower with you.

Hydro energy is electricity made using water. Sounds weird, right? Especially since it's dangerous to mix the two. The water never comes in contact with the electricity. How it works is, water flowing down a river is used to spin turbines inside a generator. Large rivers with fast flowing water work the best.

http://www.tva.gov/power/hydro.htm

http://www.north-harris.org/wp-content/uploads/2011/08/hydro-anim-en.gif