Got the winter blues? Professor Pickle’s awesome experiment will put some super swirly colour into your day. It can be a little messy, so make sure you put something under your experiment materials to protect the bench or table.
A shallow bowl or plate, full cream milk, at least three different colours of food colouring, cotton bud, dishwashing detergent.
1. Pour the milk into the bowl.
2. Squeeze a drop of each colour of food colouring into the middle of the bowl of milk, making sure they don’t run into each other.
3. Dip the cotton bud into some dishwashing detergent.
4. Place the cotton bud into the centre of the bowl of milk, making sure not to move it around. Watch the colours burst like fireworks into the milk! Now place the cotton bud into different areas of the bowl to create more colours. Notice how the colours in the milk continue to move even after you remove the cotton bud.
Q: Why it happens...
Milk is mostly water, but it also contains vitamins, minerals, proteins and tiny droplets of fat. When the dishwashing liquid is added, it reacts with the fat particles in the milk. This reaction causes the fat molecules to move around, which in turn make the food colouring molecules zip around the surface of the milk — and that creates the moving swirls of colour. As the soap mixes in with milk, you’ll see the colour swirling action start to slow down.