Rainbow Milk

Today, we were experimenting with rainbow milk. We use a small saucer of milk, add drops of food colouring in the primary colours. Then, we add a drop of dish detergent. The science behind the experiment is that the fat in the milk reacts with the soap, pushing the colours around in the milk. Often the colours blend together, making the secondary colours of purple, green or orange. Our experiment didn't work exactly as planned (I think we used the wrong kind of detergent), but the students had a great time hand mixing the colours together.