Water mostly enters a tree through the roots and travels upwards into the leaves through capillary action.

Ms Lai suggested this very simple experiment to demonstrate this action.

What you need:

1. Red, yellow & blue food colouring
2. 6 clear glasses
3. Paper Towel

What to do:

1. Start by adding water to three of the cups so that they are about 3/4 full of water.
2. Alternate each cup containing water with an empty cup and arrange them in a circle.
3. Then add a few drops of food colouring to each cup so that one cup is red, one is yellow and one is blue.
4. Next take paper towels and fold them in half or fourths to make long strips.
5. Link all the cups together using the paper towels by placing one end of each paper towel in each cup.
6. Wait a little while and watch how the water travels through the paper towels and mixes to form new colours. Amazing!

Why it works?

The water is able to move up and through the paper towel because of a process called capillary action. The water travels up the tiny gaps in the fibres of the paper towel.