Energy in a Moving System
≈ 15 minA system is a group of parts that work together to do a job. When you put energy into a system, movement comes out the other end.
On a see-saw, two friends form a system. When one pushes down with their legs (energy in), their side goes down and the other side goes up. On a bicycle, your legs push the pedals (energy in), the pedals turn the chain, the chain turns the wheels, and you roll forward.
Where does the energy to work the system come from? From the food you ate — stored energy that came from the Sun, released in your muscles to push the pedals or stamp the see-saw down.
Worked example. Follow the energy on a bicycle: food energy in your muscles → your legs push the pedals → the pedals turn the chain → the chain turns the wheels → you move. Take away any one part and the movement stops.
A group of parts that work together to do a job is called a ___. Fill in the missing word.
On a bicycle, where does the energy that moves the bike come from first?
On a see-saw, you push your side down. What happens to your friend's side?
The energy your muscles use to pedal a bike first came from your ___ — the thing you ate. Fill in the missing word.