Mechanical energy has always been very important. Older watches and clocks had a spring in them. When the spring was wound up (in a tight coil) the energy stored in the spring would run the time piece for several days.

Early record players produced music with no electricity at all. The energy was stored in a large spring and could make the record spin around and produce the sound energy.

There are several aspects of mechanical energy that you could investigate scientifically. Your group could investigate:

• how the amount of motion energy (kinetic energy) in a moving skateboard is related to the amount of stored mechanical energy (potential energy) it has at the top of the slope
• how the amount of stored mechanical energy (potential energy) in a rubber band is related to the size of the band.

Remember, in each investigation there is one variable you will change. All the other variables must be kept constant.