4.13 What is Energy? Lesson

​What is Energy?

​Energy - is the ability to do work.
Energy can neither be created nor destroyed.
Conservation - saving the total amount of something.

​A law of Energy

​law - something that always happens under the same conditions.
transfer - to move from one place to another.
universe - all of matter and space.
work - the use of force to move an object.

Multiple Choice

Energy cannot be transferred!

• True

• False

Multiple Choice

When you kick a ball, the energy transfers to the ball.

• True

• false

Multiple Choice

Energy cannot be destroyed!

• True

• False

​Thinking About Energy

​Collide - to bump into.
kinetic - having to do with motion
potential - the stored energy belonging to something.

​kinetic energy is the energy of motion.
potential energy is the energy of position or the stored energy.

​A roller coaster changes electric energy into potential energy.
It has the most potential energy at the top of the hill.
At the bottom of the hill the roller coaster has the most kinetic energy.
The potential energy convert into kinetic energy as it goes down the hill.

​In a car crash, to save people inside you want to slow the change of energy.
If you slow to quickly you will get injured very badly or killed.

​The car hits the sign and transfers its kinetic energy into the sign. The sign also changes shape - elestic energy - it stretches and heats up - thermal energy. The car will bend and also heat up elastic and thermal energy.

​When a slinky goes down the stairs it is changing gravitational potential energy in to kinetic energy and then into elastic energy and then back into kinetic energy.

​Energy on the Move!

​electrical current - the flow of electricity.
generate - to make or create.
power plant - a factory for generating power.
vibrate - to move back and forth quickly.

​Fossil fuels store the suns energy in the form of chemical energy.
We burn fossil fuels to make thermal energy and change it into kinetic energy. We then change the kinetic energy into electricity.

​Sound is the movement of energy from one place to another. the drum vibrates, your throat vibrates. This creates waves in the air.

​We can also use water in dams to turn turbines and produce electricity.
We transfer potential energy of the water into kinetic energy.
The kinetic energy is then changed into electrical energy.