This week we used the following equipment to create some a Christmas science:
~ Whole milk
~ Cookie cutters
~ Food colouring
~ Liquid dish soap
We poured a thin layer of milk into a shallow plate and then arranged the cookie cutters in their dish of milk.
The children squeezed a few drops of food colouring onto the milk within the cookie cutters and then put a drop of liquid dish soap into each cookie cutter. The colours spread out like little fireworks, but stayed within the cookie cutters. We watched the colours mix and churn.
When we were ready, we lifted the cutters and watched the coloured milk burst through its old boundaries and then they began to mix together.
The Science Part
First, all liquids have a property called surface tension, which refers to the way the molecules on the surface of the liquid bind together tightly. Surface tension is what makes liquids form a dome on the top and what makes liquids form into little individual droplets.