Warm-up 1.A light-bulb shining brightly. 2.A timer ringing. 3.A picture hanging on the wall. 4.A candle flickering in the breeze. 5.An ant crawling on the ground. 6.A piece of pizza on your plate. 7.A roller coaster stopped for that split second at the top of the first hill. KE PE KE PE Decide which kind of energy each example is demonstrating and write K.E. or P.E. next to it.

Energy Transformations Ch. 3.2

Law of Conservation of Energy Energy can not be created or destroyed. Energy changes from one form to another. Amount of energy remains the same.

Roller Coaster Energy Conversion – K.E. and P.E. are constantly converting back and forth! An coaster in motion has ___. As it goes uphill it begins losing ___, but starts gaining ___. When it stops for that split second at the top of the first hill it has full ___. Then as the coaster starts going downhill again, it loses ___ and gains ___. K.E. P.E. K.E. P.E.

Power Plants – another energy conversion! Almost all the energy on Earth began as electromagnetic energy from the Sun. Plants convert _______________ energy into ________ energy as they grow (photosynthesis). These plants died millions of years ago with the chemical energy stored in them. They turned into fossil fuels (oil, coal, natural gas). At power plants we burn these fossil fuels to make _________ energy. This electrical energy might be turned into ______________, _________, and _______ energy in your home. electromagnetic chemical electrical Light (electromagnetic) mechanicalheat

Hydro-electricity… yet, another energy conversion! 1. Water held behind dam has ___ 2. PE is converted into ____ when water moves through tunnel 3. KE is used to turn turbines. This _________ energy is turned into _________ energy by generators. 4. Electrical energy is transmitted through wires and converted into other forms of energy. P.E. K.E. mechanical electrical

Energy Efficiency Energy efficiency - a measurement of usable energy after an energy conversion. Energy-efficient household appliances convert a greater % of energy into the desired form than inefficient ones. Less electrical energy is needed to operate them too 100% electrical energy 5% heat energy 5% sound energy 90% mechanical energy

Inefficiency All the energy going into this electric fan is converted, but some of the electrical energy is changed into unwanted forms. The electrical energy is converted into: ____________ energy (fan blades) - wanted _______ energy - unwanted 50% mechanical energy 25% sound energy 25% heat energy mechanical heat sound

Wrap-up 1.___________ may not be created or destroyed, it changes forms, and amount remains the same amount. 2.The classroom clock converts the _______ energy in its batteries to __________ energy powering it to work through the wires. Then it changes into __________ energy when the hands are moving. Some wasted or unwanted forms of energy it was turned into was ________ energy when we hear it tick and ________ energy from the friction of moving parts. 3.You use ________ energy to strike a match. The match’s ________ energy allows it to burn and we can feel the ________ energy, hear the ________ energy, and see the _______________ energy. 4.The 2 most wasted forms of energy that commonly occur during energy conversions are _____ and _____. Energy electrical mechanical chemical mechanical chemical heatsound electromagnetic sound heat sound