Wobble Lab

Quick reads

The science of squish

Move the mouse down over the picture to press the jelly, up to let go (on a phone, tap to press and tap again to let go). Drag the pink knob to make him firmer or softer: a firm jelly barely squeezes, a soft one goes flat. Either way his volume never changes (left needle); the right needle is how hard the press pushes. A simplified model, made for this picture.

Four quick reads on why squishy stuff acts the way it does. Keep the jelly open in another tab and poke along.

Start here

Jelly lets you watch physics at human speed. A wobble crosses soft jelly at about 1 to 3 metres a second. In steel, it's over 3,000. Same physics, a thousand times slower. That's why jelly jiggles where you can see it, and steel rings where you can only hear it.

The reads below cover what a gel is, how firmness is measured, why it wobbles at the speed it does, and when a blob stays round or flops into a puddle.

Pick a blob

Each blob shows off one thing squishy stuff does, and lets you mess with it.

Live

Jelly

Wobbert: big, calm and a bit dramatic. A slab that keeps its volume and fights being sheared. Change how soft it is and how fast it calms down, and the whole wobble changes.

 Live

Elastic ball

Boing: zero chill. The same stuff with almost no damping, so you see a gel that loses almost no energy per bounce. No real gel acts like this.

 Live

Layered and Flowing

Ripple: smooth and unbothered, until you drag through it. A stretched skin drawn as stacked lines, with three moving pulses that add up where they overlap. It shows superposition, not a solved wave equation.

 Live

Bright and Shifting

The Glow Crew: five glowing gels, zero personal space. Their glows add up where they overlap and each gel bends the light behind it. Push them together: they flatten, bounce apart and settle.

 Watch

Sleepy and Wobbly

Seven jellies, one zig-zag. Each one drops onto a bigger sleeping one and wakes it up. The bigger they get, the slower they wobble. Sound on.

 Watch

Bouncy and Squeezy

One squishy ball bounces down the ramps, squeezes through a gap smaller than itself and lands in a wobbly gel pool. Sound on.

 Live

Plump and Squishy

A jelly and a tube that's too narrow for it. Slide it through: a soft jelly stretches into a long sausage and pops out the other end, however plump it is. A firm one gets stuck. You choose how soft and how big.

 Live

Twisty and Tubular

A jelly in a labyrinth of glass pipes, some narrower than he is. Steer him with the mouse, pick up the coins and find the star. A soft jelly squeezes round the bends and stretches like toothpaste. A firm one gets stuck at the mouth of the pipe.

The physics behind the wobble

Why jelly wobbles
and steel doesn't.

A jelly is about 90% water, held in a net of protein too fine to see. That one fact explains the wobble, the melt in your mouth, the chew of a gummy bear, and why a big jelly shakes slower than a small one.

Now try the jelly

Reading about a wobble is fine. Causing one is better. Our jelly is solved in your browser 120 times a second, and it follows the three rules real jelly follows: it keeps its volume, it fights being pushed out of shape, and it loses a little energy every wobble. That last one is why it calms down instead of wobbling forever.

Squish the jelly