Try this at home!!
Milk (whole )
Food colouring (red, yellow, green, blue)
1. Pour enough milk in the dinner plate to completely cover the bottom to the depth of about 1-2 cm. Allow the milk to settle.
2. Add one drop of each of the four colours of food colouring - red, yellow, blue, and green - to the milk. Keep the drops close together in the centre of the plate of milk.
3. Find a clean cotton bud for the next part of the experiment. Predict what will happen when you touch the tip of the cotton bud to the centre of the milk. It's important not to stir the mix. Just touch it with the tip of the cotton bud. Go ahead and try it. Did anything happen?
4. Now place a drop of dish washing liquid on the other end of the cotton bud Place the soapy end of the cotton bud back in the middle of the milk and hold it there for 10 to 15 seconds. Look at that burst of colour
5. Add another drop of soap to the tip of the cotton bud and try it again. Experiment with placing the cotton bud at different places in the milk. Notice that the colours in the milk continue to move even when the cotton bud is removed. What makes the food colouring in the milk move?