This experiment is super easy, using things that you probably already have at home.
You will need:
Three clear cups/containers
Kitchen roll
Water
2x Food colouring
What to do:
Step one: Prepare two pieces of kitchen roll by folding them length ways between 1 and 2 inches wide.
Step two: Position your three empty cups/containers about 2-3 inches apart on surface where you can see them but they aren’t going to be in the way.
Step three: Pour the equal amount of water into the two end cups, leaving the middle cup empty.
Step four: Add a couple of drops of colouring into the water and give it a stir to mix it in.
Step five: Place one of the pieces of kitchen roll that you prepared from one of the end cups into the middle one. Then take the second strip of kitchen roll and put it from the middle up cup into the other end containing the second colour.
Step six: Observe what starts to happen straight away, you should notice that the water starts to walk up the kitchen roll. Then leave the cups alone for an hour and two. When you come back more of the water should of walked along the kitchen roll and two colours should of mixed in the middle cup/container.
How does the experiment work?
Due to a process called capillary action the water moves. The adhesive forces between the water and the paper towel are stronger than the cohesive forces inside the water. As a result, the water travels up and across the paper towel out of one glass and into another.
I hope you enjoyed the experiment.
This is a great way to watch changes over time and see what happens when colours are mixed.