11-December-23
We know that there is fat in full-fat milk.
When we squirt drops of food colouring into the milk, the colours sit on top of the milk.
If we touch a cotton bud to the colours, nothing happens.................unless.........
If we first put a drop of wash up liquid on the cotton bud, and then touch the tip of the cotton bud to the colours in the milk, the colours will all spread out.
Washing up liquid does not mix with milk, instead it floats on top and spreads over the surface.
Soap breaks up the minerals, proteins and fats in the milk.
Milk fat does not dissolve in water.
When you add soap to the milk the soap molecules and fat molecules bump into the food colouring molecules and as a result we see and explosion of colour.
This is really fun to try at home!