Dancing milk

By ilehmann In News

Experiments are always fascinating for children and an excellent way to keep them busy. This time, there was “dancing milk” to discover at our Infanterix Sendling facility. In a bowl of milk, a few drops of food colouring were spread around the rim. Add a drop of dishwashing liquid to a cotton bud and dab it into the middle of the milk and then into the drops of colour. What happens next is really exciting: the colours spread out like waves, “dance” with each other and turn into spirals. Of course, we make sure to also explain to the children why this is happening: the surface tension and the fat in the milk prevent the drops of paint from mixing with the milk. When the dishwashing liquid touches the milk, the tension of the milk surface is reduced, and the colour flows away. The reaction of the dishwashing liquid with the milk molecules creates the spirals. The food colouring shows the movements and changes. Even as adults we can still learn something…