Elastic Energy

Stretch It Out

Archer

Elastic potential energy of the bowstring transfers to the arrow as kinetic energy.

In a Flash

Elastic Energy

Elastic energy is energy stored in an object when there is a temporary strain on it – like in a coiled spring or a stretched elastic band.

The energy is stored in the bonds between atoms. The bonds absorb energy as they are put under stress and release the energy as they relax (when the object returns to its original shape).

When the string of the bow and arrow is pulled back the elastic potential energy in the bow is converted to kinetic energy of the arrow when the string is released. When the arrow reaches the top of its flight, it has zero kinetic energy and the initial elastic potential energy is now gravitational potential energy of the arrow. Using conservation of energy, one can calculate how far the bow string must be pulled back in order for the arrow to reach a certain height (specifically, for the arrow to just touch the ceiling of the lecture hall).

https://sciencedemonstrations.fas.harvard.edu/presentations/bow-and-arrow

Archer

A temporary strain on an object stores elastic energy in the object.

Burning Questions

What is elastic energy?

Elastic energy is a form of potential energy, because it is stored in the bonds between atoms in an object or substance when it is temporarily under stress. This stress could be due to the object being stretched or squashed.

What causes elastic energy?

A force acting on an object can cause it to temporarily change its shape, such as when you stretch an elastic band, or squash a squishy ball with your hand.

When this happens, elastic energy can be stored in the object, ready to be released when the object goes back to its original shape – when you let the elastic band go, or loosen your grip on the squishy ball.

Slingshot

Pulling a slingshot taut stores elastic energy in the rubber.

Where is elastic energy stored?

Elastic energy is stored in the bonds between the atoms in an object or substance. These bonds absorb energy as they are stressed, and release that energy as they relax.

Think of it like a coiled spring – the spring absorbs energy when it is compressed, then releases it when it springs back out.

What are some examples of elastic energy?

As we've seen, elastic energy can be found in things like elastic bands, squishy balls, a bow and arrow, and coiled springs. It can also be found in catapults and slingshots.

Squishy Ball

The atoms of a rubber ball are under stress when the ball is compressed.

Can you think of any other objects that can be stretched or squashed to produce elastic energy?

What Do You Mean?

Elastic energy is energy stored in an object due to a force that temporarily changes its shape, such as squashing or stretching.

Potential energy is energy that is stored in an object or substance. Elastic energy is a form of potential energy – in fact, it's often called 'elastic potential energy'.

Cool Facts

You can produce your own elastic energy by stretching a muscle!

Speedy Summary

Elastic energy is energy stored in objects when they are under temporary strain, such as being stretched or squashed. The energy is released when the object returns to its original shape.