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Water on the Move

In this demonstration, students observe the effects of capillary action ... in action!

All plants need water to survive, and capillary action is how plants get that water. Water moves from the ground into the plant's roots, then throughout the plant through millions of tiny tubes called xylem. This is how the plant "drinks" water, but then where exactly does that water go?

Using a white carnation and coloured water, students can see where this water goes and understand how the parts of a plant work together to make sure it gets this important resource.

Wet and Dry Printable guide.

These activities are part of Science World's Big Science For Little Hands program. They were developed and tested with preschool and kindergarten educators.

Objectives

  • Observe how plants “drink” water and how the water travels through the plant.

Materials

  • Per Student or Group:
    1 white carnation (or a stalk of celery, or experiment with another leafy vegetable branch!)
    a clear vase or glass
    food colouring (red or blue make for the most obvious results)
    water

Key Questions

  • Where did the coloured water go? How can you tell?
  • Which parts of the carnation changed colour? Which parts did not?
  • Did the colour change happen quickly or slowly?
  • Where did the colour come from?

What To Do

This demonstration may be done in front of your class, or beforehand as observing the results is the main part, but seeing the whole process is preferable!

  1. Fill the vase or glass half-full with water. Add drops of food colouring – in this case, the more, the better! You want a nice, rich colour.
  2. Cut the stem of the carnation at an angle (a fresh cut makes it easier for the water to get inside). Sometimes air bubbles may get in and block the water from travelling up the stem; you may want to cut the stem while it’s underwater to keep air from sneaking in!
  3. Place your carnation in the vase and check on it throughout the the day. You should see results after a few hours as it “drinks” the water, but it may take overnight for the full effect to be reached.

Extensions

  • Make this demonstration an experiment with two carnations: put one in coloured water, one in clear water, and compare the results.E
  • Experiment with different colours! Carefully slit the carnation down the middle of its stem, starting about one-third down from the petals. Put each half of the stem into two different glasses filled with two different colours. Predict what will happen: will the petals be one colour only? Two separate colours? A mixture?

Other Resources

Science World | Youtube| Explore a Flower’s Vascular System