Energy Conversions Unit 9-2

Energy Conversion An energy conversion is a change from one form of energy to another. For instance, if I use a toaster, I am converting electrical energy to heat energy to brown the bread. c. THERMAL energy is released in ALL energy conversions.

Potential and Kinetic Energy I can also change potential energy to kinetic energy. If I raise a ball in the air to throw it, I have potential energy. Once I throw it, the ball has kinetic energy. This was also an energy conversion.

Elastic Potential Energy Ouch! Why did I do that? Elastic potential energy is the kind of energy that is wound up, like the energy in a rubber band or a wind up toy. You can tell a rubber band has energy, because if it snaps your skin, it hurts!

Chemical Energy Light from the sun causes chemical reactions in foods. This is called photosynthesis. Photosynthesis uses light energy to make new substances that have chemical energy. This is another example of an energy conversion. So, when you eat food, you are actually eating the sun’s energy which has been converted.

The sunlight, carbon dioxide, water, and minerals in the soil combine to form oxygen that we breathe in, and plant sugars. The plant sugars nourish the plant and nourish us when we eat them. Those are the chemicals in the plant.

Alarm Clock Battery Light Bulb Blender Hair Dryer Fan Example Starts off as Ends up as Alarm Clock  electrical or chemical Light, sound, thermal Battery    chemical Electrical, thermal Light Bulb  electrical thermal and light Blender Mechanical/kinetic, sound, thermal Hair Dryer Sound, heat, mechanical Fan Sound, mechanical

Other Examples of Energy Conversion Alarm Clock: electrical to light and sound energy Battery: chemical energy to electrical energy Light bulb: electrical energy to thermal and light energy Blender: electrical energy to kinetic or mechanical energy and sound energy Hair dryer: electrical energy to thermal energy and kinetic or mechanical energy Fan: electrical energy to kinetic or mechanical energy

Machines and Energy Sometimes we use machines to make work easier. A bike is an example of this. We use the bike to move around easier and faster. A bike converts chemical energy in your body to move the pedals which gives the bike kinetic energy.

Quickie Quiz If you are about to jump into the pool, is this potential or kinetic energy? 2. If you are skateboarding down the street, is this potential or kinetic energy?

Quickie Quiz 3. What is the energy conversion taking place when you use a television? 4. What is another example of energy conversion you might see around your house or school?