Transfer Transformation Energy Transfer Transformation and Conservation The

Transfer & Transformation Energy Transfer, Transformation and Conservation

The Law of Conservation of Energy • Energy is never created or destroyed! • The total amount of energy will always remain the same! E = mc 2

• • Chemical, thermal, radiant, and electrical are some of the forms that energy can have. In the world around you, energy is transforming continually between one form and another.

Energy Transfer Transformation

Energy Transfer vs. Energy Transformation • Energy TRANSFER is the passing of energy from one object to another object.

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Energy TRANSFORMATION is the changing of energy from one form of energy to another form of energy.

Example of Energy Conversion • Toaster Electrical Heat Light Mechanical Kinetic

Example of Energy Conversion • Flashlight Mechanical Kinetic Chemical Electrical Light Heat

Example of Energy Conversion • Car Mechanical Kinetic energy Chemical Electrical Light Heat Mechanical Kinetic

Example of Energy Conversion • Calculator Solar energy Electrical Light Heat

When Energy is Transferred or Transformed not all Energy is changed into useful energy, some will be changed into energy that is useful. Energy efficiency is how much useful energy you can get out of a system.

Examples of Efficiency • The human body is less than 5% efficient…. most energy is transferred to heat energy. • An incandescent light bulb converts 10% of electrical energy into light and the rest is converted into thermal energy. • Electrical Power plants are about 35% efficient.

Friction -- Heat • During these transformations some energy may be released in the form of heat (friction). • No machine is 100% efficient because friction transforms mechanical energy to thermal energy.

Energy and Friction • Friction slows down • kinetic energy Mechanical energy is converted to thermal energy, so kinetic energy is not lost but simply converted to this thermal energy

Tracking Energy Transformations • As the mountain biker pedals, his leg muscles transform chemical energy into kinetic energy. • Kinetic energy of his leg muscles transforms into kinetic energy of the bicycle as he pedals. 17

Tracking Energy Transformations • Some of this energy transforms into potential energy as he moves up the hill. • Also, some energy is transformed into thermal energy. • His body is warmer because chemical energy is being released 18

Tracking Energy Transformations • Because of friction, the mechanical parts of the bicycle are warmer, too. • Thermal energy is almost always produced by an energy transformation. 19

Tracking Energy Transformations • Because of friction, the mechanical parts of the bicycle are The energy transformations warmer, too. that occur when people • Thermal energy is exercise, when cars run, when almost living things grow and evenalways when stars explode, all produced by an produce thermal energy transformation. 20