This simple science experiment explores density using oil and water. It also explores the concept of light and colour travelling at different speeds.
What your child will discover in this experiment is that oil is less dense than water, so it will float on top of the water.
How it works:
The food colour in the oil travels at different speeds forming a rainbow in the water underneath. Oil and water do not mix. Oil is less dense than water and floats on top of the water. When you add the food colour to the oil it will not mix. Once you add the oil to the water, the coloured droplets start to drop down since they are heavier than oil. Once they drop into the water they start to dissolve and look like tiny explosions.
- Fill your jar 3/4 full of water.
- Add oil into a bowl.
- Add 4 -5 drops of food colour for each colour you want to add. Preferably red, orange, green and blue.
- Whisk the food colour into the oil.
(tip: It’s best to whisk and add the oil straight into the jar before the food colour settles on the bottom of the bowl or it may not form droplets when you add it to the water.)
- Gently add the oil into the water so that it settles at the top.
- Watch as the little drops start to come down from the oil.
Promote learning by:
Talk to your child about what they observe. Why does the oil sit at the top of the jar? Why does the colour fall down and explode in the water? What colours can they see?