Always wear eye protection during science experiments. Never handle sharp objects, open flames, chemicals, or other dangerous objects without adult permission and supervision.
In this experiment, we'll learn about something called capillary action. Capillary action is fascinating because it allows liquid to move by itself––against gravity!
Capillary action occurs because water has strong cohesive and adhesive properties, meaning that it likes to stick to itself and to other objects. In celery and other plants, water moves from the roots to the leaves through capillary action in small tubes throughout the plant's tissues, called xylem.
Place the celery stalk into the cup so that it's standing up by itself. We just used one celery stalk, but you can do this experiment with as many as you'd like.
Fill the cup with a couple of centimeters of water.
Add one or two drops of food coloring. If you feel like being creative, you can use two different colors to make a compound color.
Now, the hard part: be patient. Observe your celery every few hours and watch as the colored water makes its way up through the celery. How fast is it moving up the celery?