Pour honey, then dish soap, then coloured water, then oil into a tall clear jar, one layer at a time, watching each new liquid settle into its own band instead of blending. Drop in small objects to see which layer catches each one.

What you need

a tall clear jar
honey
dish soap
water (food colouring optional)
vegetable oil

How to do it

1Pour honey into the jar first, filling about a quarter of it.
2Slowly pour dish soap down the side of the jar so it settles on top without mixing.
3Add coloured water the same slow way, then oil last.
4Drop in a coin, a bead, and a small toy, and watch which layer stops each one.

Variations

If pouring slowly is tricky: pour down the back of a spoon held against the jar's inside wall to slow the stream further.
How it ends: a final guess-and-check round -- 'where will this object land?' -- caps the investigation.

💡 Parent tip

Let a failed pour (layers that mix) happen once — comparing the messy jar to a clean one is often more instructive than getting it right the first time.

What your child develops

Density as a concept — seeing liquids settle by weight rather than mixing is a genuinely surprising, memorable demonstration
Prediction and testing — guessing where an object will land before dropping it builds hypothesis-testing habits
Careful, controlled pouring — a real fine motor challenge at this age