We did a really cool and colourful experiment this week that was very engaging. This cool experiment made some beautiful patterns using just a few things and we learnt about why this happened.
What do you need for this experiment?
- Washing up liquid
- Food colouring (we had red, blue and yellow)
- Cotton bud
- Dish to put the mix in – we used a clear lasagne dish
Pour some milk into the dish (enough so it covers the bottom and has enough to move around) and then add some drops of food colouring in random places.
Then dip your cotton bud into the washing up liquid and put it into the food colouring. The food colouring tries to get away from the washing up liquid and creates some really cool patterns.
Why does this happen?
First let’s look at some of the science behind each of the items we are using:
Soap is made up of molecules, and each end is either water loving or water hating. This is the washing up liquid.
Milk is made up of vitamins, minerals, water and fat and:
Water molecules are called polar molecules and they can dissolve any other polar molecules.
Fat molecules are called non polar molecules and cannot dissolve in water.
When soap is added to the mild it starts to separate the water and fat in the milk – the water hating molecule of soap breaks up the fat, and the water loving molecules get with the polar (water) molecules. The soap is connecting them and the fat molecules move away crating the colour patterns in the milk.
The colour patterns start to slow down because the the soap has attached to most of the fat molecules, and will take over the mixture. If you add more soap the explosion may start again if there are still fat molecules left.