How Energy Changes Form     Energy often changes from one form to another. For example, the mechanical energy of a moving drumstick changes to sound energy when it strikes the drumhead and causes it to vibrate. Any form of energy can change into any other form. Frequently, one form of energy changes into two or more different forms. For example, when wood burns, the wood's chemical energy changes to both thermal energy and light energy. Whenever energy changes form, energy is conserved. No energy is lost, although some may be released as thermal energy due to friction.     Many machines... Show more

How Energy Changes Form    
Energy often changes from one form to another. For example, the mechanical energy of a moving drumstick changes to sound energy when it strikes the drumhead and causes it to vibrate. Any form of energy can change into any other form.

Frequently, one form of energy changes into two or more different forms. For example, when wood burns, the wood's chemical energy changes to both thermal energy and light energy. Whenever energy changes form, energy is conserved. No energy is lost, although some may be released as thermal energy due to friction.    
Many machines change energy from one form to another. For example, a turbine changes mechanical energy to electrical energy. Some of the mechanical energy of the moving parts is used to overcome friction. The more efficient a device is, the less energy it uses to overcome friction and the greater the percentage of usable energy it produces. The U.S. government's Energy Star program certifies the energy efficiency of appliances. Appliances with an “Energy Star” label use energy efficiently and thereby reduce energy use.    

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