The movement of water in celery is an example of capillary action. Capillary action is important in both plants and humans.

In plants, water moves up from the roots through the stem and into the branches and leaves. When water moves through the stem, it contains nutrients and minerals the plant needs to survive. The movement of water allows various areas of the plant to receive these nutrients and minerals.

In humans, capillary action is seen through blood vessels. Similar to roots in plants, blood moves through the blood vessels that contain oxygen, nutrients, carbon dioxide, and waste products. The transport of blood with its nutrients is how the rest of the human body receives these nutrients.

Here you will observe water moving up a plant using a stalk of celery. The water will be filled with food coloring to easily visualize the movement of water within the celery. After a few hours, the color from the water should be seen at one end of the celery stalk.

Step 1: Gather All the Required Materials

For this experiment you will need:

a stalk of celery
water
food coloring
clear plastic cup
knife

Step 2: Cut the Celery

Using a knife, cut the celery into 3 pieces about 6 cm long or about the size of your pointer finger. Each of the 3 pieces of celery should be cut differently:

the first piece of celery should include the leaves of a celery on one end of the celery
the second piece of celery should be cut evenly on both ends of the celery
the third piece of celery should be cut unevenly with some of the skin of the celery separated from the rest of the celery (see the left celery in the picture above)

You will use the celery to see the movement of water within plants. Celery is a good plant to use to observe the movement of water because the skin covering the celery is clear enough for you to see the xylem. The xylem is the tube within plants that allow water to move up from its roots to other areas of the plant.

Step 3: Add Water

Using a measuring cup, add ¼ cup of water into a clear plastic cup.

The water will be used for the celery to absorb to show the capillary action in plants.

Step 4: Add Food Coloring

Add 3 drops of food coloring into the cup filled with water. Mix the food coloring in the water using a spoon.

The food coloring will help you see the water movement in the celery.

Step 5: Place the Celery in the Cup of Colored Water

Place the celery in the cup of water vertically so that only one end of the celery is in the water while the other end of the celery should be outside of the water.

Step 6: Allow Celery to Absorb Water

Let the celery sit in the water for overnight or at least 6 hours.

If you perform the experiment during the day, check the celery every two hours. If the food coloring is seen at the opposite end of the celery before six hours, move to step 7 and make observations of the celery.
If the experiment takes longer than six hours, use new pieces of celery and add 2 more drops of food coloring to the water.

Step 7: See the Water Movement Through the Color Change

After letting the celery sit for a few hours, you should see the food coloring at the opposite end of the celery stalk that was not submerged in the water.

For the celery that is cut evenly, you should see colored dots at the end of your celery stalk.
For the unevenly cut celery, you should see the color as lines along the edge of the celery.
For the celery that has leaves on the end that is not submerged in water, you should see the color change in the leaves.