This is a classic science experiment for small children meant to teach them how water travels up a plants stem.
- A disposable clear drinking glass
- A stalk of celery, with leaves
- Food coloring (dark colors will work more noticeably than yellow)
- A drinking straw (optional)
- A knife
Fill the drinking glass half way with water. Dye the water heavily with food coloring. I used about 10 drops of food coloring per glass. Cut off the bottom of the celery stalk and place it into the glass with leaves intact. If the leaves are intact the colored water will travel all the way up the stalk and color the leaves, but if the leaves are not intact you will still be able to observe the dye traveling up the celery stalks capillaries.
Place the celery stalk in the colored water leaf end up. Allow the celery to drink overnight (at least 12 hours).
After the celery has had its drink, you’ll notice that the leaves (or the top end of the celery stalk, if yours did not have leaves) have begun to change color. Show the child the drinking straw and explain that the celery stalks capillaries (the stringy parts) act like a drinking straw, and allow the celery to carry water from the earth (or the cup) up through the stalk to its leaves.
Next, show the child the end of the straw, and observe that although the straw is shaped like a long cylinder, when viewed from the end it looks like a small circle or dot.
Cut the celery in half and show the child the cross section. The insides of the capillaries will be dyed very dark. Explain that these are the capillaries, or straws, through which the dyed water has traveled.
This experiment can also be done with white carnations or Queen Anne’s lace. The result will be that the white flowers will be dyed the color of the colored water.