I love how simple, but exciting this experiment is. It is really easy science for kids to do at home, or school! All you need is water, clear cups, oil and food colouring! There is so much learning that happens with this experiment, from learning about how oil and water interact to colour mixing and density. There was a lot of excitement in the room as we did the experiment. Many students commented, as they did their experiment that it reminded them of fireworks.
I filled a cup 2/3 full with water. I also filled another very small cup with about a tablespoon of oil. Then, I added a few drops of food colouring to the oil. I asked children to stir their food colouring to mix it into the oil with a toothpick. They were immediately surprised to find that they couldn’t mix it! The oil remained separate from the food colouring! (This mixing does however break the food colouring apart into smaller drops.)
I paired students up and made sure that each of the partners had a different colour of food colouring in their oil. One at a time, they then slowly poured their oil into the water. They watched as the oil floated to the top of the water and did not mix. With magnifying glasses, they then watched as the food colouring slowly ‘popped’ down into the water. (The food colouring is heavier/denser than the oil so it sinks.)
Children loved watching as their two colours met and began to change the colour of the water. Once all of the food colouring had fallen, I had students try and mix the oil in. It is almost mesmerizing to watch the oil move through the water, but always settle on top. This also teaches children that although water and oil are both liquids, they behave in different ways and have different properties.
I love how beautiful all of the cups looked as we did this easy science for kids! My students loved their ‘fireworks’ they created and the fact that they were much quieter than other fireworks. I love kindergarten!