Energy

What is energy? ENERGY is the ability to cause change. There are many different kinds of energy. Everything around us has energy – YOU have a large amount of energy. When change occurs, energy is transferred from one object to another. – Footsteps transfer energy from foot to ground to ears. – Warmth is felt when the sunlight transfers energy to a table or chair. – Where do you see energy?

Energy of Motion KINETIC ENERGY is the energy an object has due to its motion. KE = ½ x mass x (velocity) 2 The faster something is moving, the more kinetic energy it has. The heavier a moving object is, the more kinetic energy it has.

Energy of Position POTENTIAL ENERGY is the energy an object has based on its position. PE = mass * gravity * height Objects very high up have lots of potential energy.

Total Energy The TOTAL ENERGY is the combination of kinetic and potential energy of a system. TE = KE + PE The LAW OF CONSERVATION OF ENERGY states that energy can neither be created nor destroyed – it only changes forms.

Phet demonstration We are going to look at an online demonstration, and decide where potential and kinetic energy are the highest. – What is happening as the skateboarder goes up/down the hill? – What is happening to their total energy? – What happens if we change the ramp?

Practice! ws ws Where is Lenny’s potential energy the greatest? What happens to his kinetic energy as he rolls down the hill?

Draw a picture of what Lenny’s path might have looked like. What happens to Lenny’s potential energy as he rolls down the hill? What happens to his total energy? At the very end, where does all the energy from his motion go?

Activity! – Human Continuum During this activity, you will be asked to stand in an area of the room that represents your answer to a question. You may be asked to defend your answer – be ready to give your reasoning!

A skater starts at the top of a ramp. Is his energy: Potential? Kinetic? Thermal?

A skater is at the bottom of the ramp, quickly moving up to the other side. His energy is: Kinetic, potential, or a mix?

Where is this skater on the ramp, given his energy? Top (up) bottom Middle top (down)

Same question – where is this skater? Top Middle bottom

Top Middle bottom

In which position does the skater have the most…? Kinetic energy Potential energy Total energy

At the highest point kinetic energy is zero / maximum while the potential energy is zero / maximum. At the lowest point kinetic energy is zero / maximum while potential energy is zero / maximum. Mass affects / does not affect the amount of energy. As an object falls in gravity, kinetic energy increases / decreases / remains the same. As an object falls in gravity, potential energy increases / decreases / remains the same. As an object falls in gravity, total energy increases / decreases / remains the same. An object travelling faster and faster has a kinetic energy that increases / decreases / remains the same. An object travelling faster and faster has a potential energy that increases / decreases / remains the same. As an object speeds up, the total energy increases / decreases / remains the same. As an object slows down, the total energy increases / decreases / remains the same.