Energy exercise for February 19:

All living things need energy. When Mark Dane helped us explore how solar cells and batteries can power lights and motors, we saw that energy is converted to other forms of energy (like radiant/light or mechanical/motion), and that some sources can provide for a long time (as long as it is sunny!). Which was more powerful? Hard to say--think we need more experimentation!

Our lists:
Where does energy come from?
Sun, stars, nuclear reaction--produce thermal/heat and radiation/light energy by nuclear fusion of hydrogen and helium
Nutrients--food is potential energy produced by converting sunlight to chemical energy
wood--as it burns, providing thermal/heat and radiation/light and chemical energy from oxidation
fire, lightning--provide thermal/heat energy and radiation/light
batteries--store potential chemical energy, when used, its electricity
earth's core, the moon, magnetism, electricity--produce mechanical energy

How many forms are there?
Potential energy is stored energy
Kinetic energy is the energy of moving things
Radiant/light, chemical, electrical, thermal/heat, mechanical--describe conversions by some mechanism

Can it be lost?
We said no (8 to 2) it is converted to other forms

We found many conversions during our experimentation with the leds and small motors. The batteries provide electricity for conversion to both light (leds) and mechanical (motors), and the solar cells changed radiation to electricity which did the same things. We also noted that thermal/heat energy often went along with these conversions. You said that energy from a solar cell is more powerful than energy from a battery, what if the sun is not shining for a long period?