Water is important to all plants – especially in the garden at YGP! But how does water move through plants? By performing the Rainbow Root Systems Experiment, we will learn how plants take up water through their roots! We will also get some practice using the Scientific Method, which is the process or method of conducting research used by scientists all over the world!

Key Terms

Transpiration – the process of water moving through a plant and its evaporation from its leaves, stems and flowers

Xylem and Phloem – vascular tissue of a plant that transports water, sugar, and nutrients throughout the plant and its parts (acts like a straw)

Adhesion – the process of water sticking to other substances

Cohesion – the process of water sticking to other water molecules

Capillaries – tubes in the roots, stems, and branches of plants

Capillary Action – a property of water allowing it to flow in narrow spaces without the assistance of gravity (occurs when adhesion is stronger than cohesion). Think about how water “climbs up” a paper towel when you get it wet! This is capillary action at work!

Let’s Go Over the Steps of the Scientific Method!

  1. Question – what are you curious about? Ask a question about something you want to know the answer to.
  2. Hypothesis – make an educated guess about what you think will happen.
  3. Experiment – test your hypothesis!
  4. Analysis – make observations about what happened. Talk about it with someone or write down what you notice.
  5. Conclusion – the end result of your experiment! A conclusion either helps you state that your hypothesis is TRUE or your hypothesis is FALSE.

Experiment Materials

  • 3-4 Jars or clear drinking glasses
  • Water
  • Food coloring (Choose how many colors you want to experiment with! Note: red and blue pigments tend to work well for this activity) 
  • Spoon
  • 1 Bunch of celery OR white carnations


Go over experiment instructions and develop a hypothesis using an “if-then” statement. For example, IF celery is placed in colored water, THEN the celery will change color.

Now it’s time to move on to the experiment stage. Gather materials and find a spot to set up your experiment. Fill each jar about 1/2 full with water. Squeeze about 6-8 drops of food coloring in each jar (try a different color in each!) and mix with a spoon. Adding enough food coloring to the water will make the results easier to see later!

Divide celery stalks and place into each jar. You can trim the bottom of the stalks to make sure they fit and can place one or more stalks in each jar. Using the whiter parts of the stalk will show color better. If using carnations, trim the bottom part of the stems before you place flowers in each jar.

Let celery or carnations sit. Check on them in a few hours and see how the colors start to change! If you let the experiment sit overnight or for a couple of days, you’ll see even better results.

Write down observations together as you check in on your experiment.

Results and Discussion Questions

Talk with each other about what you observed:

  • How did the celery or carnations change over time? 
  • Can you see how water moves up the stem and through all parts of the plant? What else could water carry through a
  • How did this experiment illustrate the concept of transpiration?
  • What conclusions can we draw from this experiment? (think back to our hypothesis, and if it was proven true or false)

Now you have completed an experiment, using the same methods a scientist would! Now think about what other natural systems you are curious about. What other experiments can you perform, using materials from around your house, yard, or neighborhood? Good luck scientist!