A few weeks ago, while watching the movie Superman, I found out that Superman derives his great power from the Sun. All of us on this planet derive most of our power from the sun too. The basic forms of light and heat energy are delivered directly to us from the Sun everyday.
Green plants need sunlight to produce food, which in turn can be eaten by us or by animals. Thus, the entire food chain depends on solar energy for survival. This is why in several ancient cultures the sun was respected and worshipped by the people.
Today's industrial world is supported by the energy sources of oil (petroleum), coal, and natural gas. However, did you know that all of these are essentially derived from solar energy too? These fuels, also known as fossil fuels, are formed from the remains of plants and animals which existed millions of years ago.
Again, it is the heat from the Sun that causes different parts on earth to heat up at different rates. This temperature difference between the air at various locations leads to winds, and consequently our use of wind energy. The evaporation of water to clouds followed by rains and the flow of water in rivers depends on the Sun too.
Thus, we depend on the Sun directly or indirectly for almost all our energy needs. The only form of energy that is not derived from the Sun is nuclear energy. Since solar energy that comes as heat and light is a free resource, we should try to use it as much as possible.
Remember to draw your curtains apart on sunny winter days to let the Sun in and bask in the warmth. In the summer and fall, we can also use the Sun to dry our washed clothes without using a clothes dryer! We can also use solar collectors and solar cells to tap the energy of the sun directly (ask your parents for more about this).
For more information and projects on solar energy, feel free to explore the links given below:
- Government Energy Kids Site: http://www1.eere.energy.gov/kids/solar_heating_and_you.html
- Solar Now: http://www.solarnow.org/
- Solar Energy International: http://www.solarenergy.org/resources/youngkids.html
Little Lion Experiment:
We will try to do some experiments to show how different colored objects absorb or reflect light.
Items Needed:
- A really sunny day! (it might be a little hard to get this!)
- Plastic bottles - small soda bottles work well (2 or 3 bottles of same size).
- Black paint or aluminum foil
- Some tape
- 2-3 small balloons that would fit the bottle top.
- Paint one of the bottles white if you can or use a clear bottle.
- Paint another bottle with black or take some aluminum foil and wrap around the bottle with shiny side facing outward and tape it so the foil stays on the bottle.
- Place the open end of one small balloon on the mouth of the white bottle and do the same for the black bottle. Make sure the balloon forms an air tight seal. Now place both bottles in bright sunlight.
- Observe what happens. Record your observations.
Questions:
- Which balloon started filling up first? Which bottle feels warmer?
- Does heat make air expand?
- Does a black object get warmer in the sunlight than a white object?
- What would be a good color to paint a dog kennel if you wanted it to stay cool in the summer?
