- Mix about a teaspoon of food colouring in the water.
- Cut the clery stalk about 2 cm from the bottom.
- Place the celery stalk with the leafy side up in the coloured water. Let the celery sit in the coloured water for about an hour or two.
- After this time, the colour should have spread to the top of the leaves. Take it out of the coloured water and cut across the stalk. A row of tiny circles outlined in the colour you used should be present.
- Ask students, based on what they see, what may be some explanations of how water flows in trees.
(The tiny circles were cut ends of fine long tubes that exist all the way up to the top of the celery stalk. This is where water travels through, and trees also have similar tubes for water.)