Cornstarch thickening fluid (Maïzena)
Some mixes feel liquid when you pour slowly and solid when you poke or squeeze hard.
The experience
Start with water, then spoon in Maïzena until the mix feels fun: pours like a liquid, but goes firm when you slap, smash, or squeeze it. Pour with cups, pound with toys, poke and drip — then rinse everything and wipe down.
SAY THIS
Words at the table
Ages 1–2
- [I will fill this after Saturday]
Ages 3–5
- [I will fill this after Saturday]
RUN THIS
How to run it
Water first, then spoon Maïzena until the mix feels fun: flows on a slow pour, firms up on a smash or squeeze.
Setup
Cover the table; shallow water in a wide bowl; cups and washable smash toys ready; Maïzena box nearby.
Steps
- 1
Water + tools
Pour a shallow pool of water into a wide bowl on a wipeable tray. Set cups and smash toys nearby.
- 2
Maïzena until fun
Spoon in Maïzena a little at a time until it feels fun — firm when you poke or smash, still drips when you pour. No exact ratio.
- 3
Pour vs smash
Slow pour with cups flows; fast smash with a toy feels firm.
- 4
Play
Pour, smash, scoop, slap; try a ball that melts when you stop squeezing. Too watery or too powdery — steer with water or Maïzena.
KNOW THIS
What’s happening
Mechanism
The bowl is packed with tiny starch grains suspended in water — not dissolved, just floating and jostling. When you pour slowly, the grains have time to slide past each other, so the mix flows like a thick liquid. When you hit, slap, or squeeze hard and fast, the grains suddenly jam into each other. For a moment the pile locks — it feels solid — then when you ease up, the jam breaks and it melts back into a puddle. That firm feel is not a new material. Same water, same starch. What changed is how hard and how fast you pushed. A slow pour and a hard smash are two different stories about the same grain pile. Flour + water usually will not give you the same sharp switch. Cornstarch grains are the right size and shape to jam under sudden stress. That is why this kitchen mix is famous and flour goo is not the same show.
Does not prove
It does not prove the mix is “magic slime” or a different chemical each time you touch it. Same ingredients; the feel changes with how hard and how fast you push. It does not prove it turns into a rock forever, or that all kitchen powders do this.
Go deeper
Under sudden stress the particles lock (jamming); under gentle shear they flow. Flour + water usually won’t give the same sharp solid/liquid switch.
Name for this
Shear-thickening / particle jamming — optional labels after the plain story. Also called a non-Newtonian fluid or oobleck.
Trap 1
- Wrong
- It’s a solid that turns into a liquid when you’re gentle.
- Why
- That flips the cause. Hard/fast makes it jam (solid-like); slow lets it flow (liquid-like).
- Replace
- Slow = runny. Hard smash = stiff — then it melts when you stop.
Trap 2
- Wrong
- You need an exact recipe or it won’t work.
- Why
- Feel matters more than a ratio. Too watery or too powdery just needs a splash of water or more Maïzena.
- Replace
- Add Maïzena until it feels fun — firm when you poke, still drips when you pour.
Notes from home
Ran at home (Nicolas): water first, then Maïzena until it feels fun; prep cups to pour and toys to smash the mixture — logged as tested.
Stretch it
Walk fingertips across a tray of the mix (quick steps stay up; slow ones sink). Compare with flour + water.