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ELI5 Yahaaa

Storing a push

How Do Springs Work?

Bend something and it wants to snap back. A spring makes that useful.

Squash it Energy stored Let go EnergyreturnedStore andrelease
A spring is a way of keeping a push for later.

  1. Step 1 of 5

    Materials resist being deformed.

    A spring Atomic bonds stretchedout of place

    The atoms in metal are held at set distances by strong bonds. Push them closer or pull them apart and they pull hard to return to where they were.

  2. Step 2 of 5

    A coil makes a lot of bending easy.

    A steel rod Almost no giveThe same steel coiled Squashes easily andsprings back

    Solid steel barely flexes. Wind the same steel into a helix and squashing the spring gently twists the whole length of wire — a big, easy, springy movement.

  3. Step 3 of 5

    Twice the squash, twice the push back.

    Squashed 3 cm3x the push backSquashed 2 cm2xSquashed 1 cm1x

    Springs follow a simple rule: the force is proportional to how far you deform them. Double the compression and you double the push. That is Hooke's law.

  4. Step 4 of 5

    The energy is stored, not lost.

    1 You do worksquashing it2 Energy storedin bent bonds3 Released asmovement

    Work you do squashing a spring is kept inside it. Release it and you get almost all of it back — which is why springs power watches and launch pinballs.

  5. Step 5 of 5

    Push too far and it never comes back.

    Within the limit Returns exactly toshapePast the limit Permanently deformed

    Every spring has an elastic limit. Stretch past it and the atoms slide into new positions permanently — the spring stays bent.

    Car suspension, mattresses, clothes pegs, retractable pens and trampolines are all this one idea.

The short version

A spring stores the work you put into deforming it and hands it back when it returns to shape.

Try it yourself

Stretch a rubber band, hold it to your lip, then let it relax. It goes warm and then cool — you can feel the energy moving.

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