Baseline (Aiming for 4): Identify useful and wasted energy during energy transfers and measure friction. Further (Aiming for 6): Describe energy dissipation and how this reduces the capacity of a system to do work. Challenge (Aiming for 8): Apply the concept of energy dissipation in a wide variety of scenarios.

A television Heating transfer Thermal store (in the air) Chemical (in coal) Electric current transfer Wave transfer (as light and sound)

An electric drill Thermal store (in the air) Chemical Store (in coal) Electric current transfer Force transfer Kinetic Store Wave transfer (sound)

Gravitational potential store An rising lift Kinetic Store Gravitational potential store Chemical Store (in coal) Electric current transfer Force transfer Thermal store (in the air)

Useful vs. Waste energy Useful energy is energy in the place we want it and in the form we need it. Wasted energy is the energy that is not useful and is transferred by an undesired pathway.

Useful vs. Waste energy Wasted energy is eventually transferred to the surroundings, which become warmer. As energy dissipates (spreads out), it gets less and less useful.

What’s wrong? What is wrong with these statements about energy and friction? When a car stops at traffic lights, the speed energy is destroyed by the brakes and is lost. When fuel is burned in a car engine, energy is created to make the car move. When a car brakes, the thermal energy from the brakes slows the car down. Write corrected versions of each statement.