1What the tiny pieces are doing
Water holds hands. Oil won't join in.
Everything here is made of molecules far too small to see. You only need two ideas about them. Watch each one:
Water grabs water
Water molecules pull on each other really hard — like a crowd all holding hands. They squeeze together into the tightest group they can.
Oil won't hold hands
Oil molecules don't join the water's hand-holding. They only stick to each other, so the water crowd shoves them aside into their own clump.
2Two crowds that won't mix
Water-lovers next to water-haters
Put the two crowds next to each other and neither one will hold hands across the line. That's the whole reason they split:
Hold hands tightly
Each one grabs its blue neighbors and pulls into a packed, tight crowd.
Stick to their own
Gold oil molecules only hold their own kind, so the water squeezes them out together.
3Your turn — shake the jar
Shake plain oil and water as hard as you like
Tap the button to shake. The harder you shake, the more the oil breaks into little drops. Watch what happens the moment you stop — keep an eye on the gold:
4Now add a matchmaker
Two jars. One gets a drop of soap. 🧼
Same oil, same water in both jars — but the right jar gets one drop of soap stirred in first. Soap is a funny molecule with two ends: one end loves oil, the other loves water. Guess what it does, then shake both.
Guess before you shake
You shake the plain jar hard, then shake the jar with a drop of soap. After the shaking stops, which one stays mixed?