Very easy experiment to learn about basic colours and water properties. Fill some glasses half way or less with water and add food colouring. Place an empty glass in between each colour and create a bridge using fabric or paper towels. Hypothesis/Question: Will the water travel to the empty glasses? Will we get new colours?
Explanation: the water moves because of a process called capillary action. Its molecules stick together and they also stick to the fibres of the cloth/paper. The attraction force between the water and the paper towel are stronger than the forces between the water molecules,which allows water to move from one glass to the other.
Applicability: Plants are the best example. When you pour water to the plants the water gets absorbed by the soil and through cappilary action water moves through the stem to the leaves for photosynthesis. Other examples: tears