Week 1 Nature – Experiment: Traveling Water
Have you ever wondered how plants are able to pull water out of the ground? It’s not like they have a heart to pump water around or even a digestion system to extract the water from the soil! Try this experiment at home to find out how water travels through plants.
- 3 pieces of celery
- Scissors or knife
- 3 clear cups
- Food coloring (red or blue are easiest to see)
- Observation sheet or journal
- Magnifying glass (optional)
- Cut 3 celery stalks to similar lengths.
- Fill up the 3 clear cups with the same amount of water.
- In the first cup, don’t add any food coloring. This is your control. In the second cup, add one drop of food coloring. In the third cup, add 7 drops or more of food coloring.
- Add in a celery piece to each cup.
- In your experiment journal or on an observation sheet, write the start date and time of your experiment.
- Record your observations of each celery stalk in their cup after 2 hours, after 5 hours, after 24 hours, after 48 hours and after 72 hours. Make sure to compare the differences between the 3 jars.
- Take each of the stalks of celery, and slice it in half. What do you notice about the inside of the celery stalk? Record your observations. Make sure to compare the differences between the 3 jars.
What’s going on?
You probably noticed the red color slowly move up the celery stalk. Although plants don’t have circulatory systems like animals, they do have something quite similar—a network of small tubes called xylem, used for carrying water and nutrients through the entire plant. The colored water was moving up through the xylem tubes of the celery stem.
Xylem is composed of long, hollow tubes formed by overlapping cells. Plants contain many xylem vessels stretching from the roots to the tips of the leaves, just like a series of drinking straws. When you sliced the celery in half and saw colored dots in the cross-section of the stalk, you were actually looking at the xylem vessels!
Want to go even further?
- Try using celery stalks with leaves still on them. Do you notice a difference between how much water is soaked up by celery with many or fewer leaves?
- Try this experiment using leaves collected from outside. You should see the color move up the stem of the leaf and then into the veins of the leaf itself.
- Try this experiment again comparing fresh celery versus older, dried out celery. Does one soak up water and coloring more quickly than the other one? Why do you think that is?
For more information on water movement in plants: