Let’s see how you did! If you didn’t get a few of these, don’t let it stress you out – it just means you need to play with more experiments in this area. We’re all works in progress, and we have our entire lifetime to puzzle together the mysteries of the universe!


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Answers:
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  1. Solar cells, wind turbine, hydro (water) power plants, fuel cells.
  2. Renewable energy is the energy created from natural sources, like sunlight, water, wind, and temperature differences (geothermal).
  3. Power measures how quickly work can be done.
  4. Energy is the ability to do work. Work is moving something against a force over a distance.
  5. A solar cell converts sunlight straight into electricity by using a special material that allows electrons to be knocked out of their shells when hit by a photon. The free electrons are directed into flow of DV current.
  6. The source of power comes directly from the radio waves themselves.
  7. Wind turbines spin big coils of wire around very powerful magnets when their propellers (which is attached to the motor shaft) rotate.
  8. Yes, they are the same object, but it’s how you use them that makes them different.  A motor uses electricity (applied to the terminals) to rotate the shaft, and a generator rotates the shaft to create electricity at the terminals. If you spin the shaft of a motor with your fingers, you can measure a voltage at the terminals.
  9. No. A water molecule requires energy to split it apart (endothermic reaction). When the opposite occurs – hydrogen and oxygen combine, the reaction is exothermic (gives off energy).
  10. Much more energy is released from splitting a proton than an atom.  The forces that hold together a proton are much greater than the furthers that bind an atom.
  11. When you combine oxygen and hydrogen together, it makes water and a puff of energy. That’s what a fuel cell does. Most fuel cells are reversible, meaning that you can fill their tank with water and leave them out (with their solar panel pointed toward the sun), and the solar cell will split apart the water molecule and store the gases in separate tanks.  When you’re ready to drive your car, the fuel cell switches so it now combines the gases to create electricity to turn the motor (which turn the wheels of the car).

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