Camp Yellow Scope: Tints & Tubes

Howdy Campers!

Welcome to week 4 of Camp Yellow Scope: Tints & Tubes. Who's ready to have some fun with science?

Click here if you’d like to download printable instructions. You can also print out a lab worksheet to record your observations, jot down ideas, and design your own experiments! If you collect your worksheets together from all eight weeks, by the end of the summer you will have your very own Camp Yellow Scope notebook! You can even add some extra sheets for new experiments that you design yourself.        

Experiment 1: Up goes the water

You’ve probably watered plants in your house or garden. Have you ever noticed that when you water the plants, you water the soil and not the leaves and flowers? How does the water gets to all parts of the plant? Is there a magical elevator in the stem that pulls the water up?

This week we are going to do experiments to explore how water moves through plants. All you need is water, food coloring, and a stick of celery!

Let’s get started

Clear a space on the kitchen counter, your desk, or the picnic table in the backyard. Put on some clothes that can get messy, and get ready to do science!

Hypothesis

What do you think will happen when you put a celery stalk into colored water?
Record your hypotheses in your worksheet.

Instructions

1. Put on your safety goggles.
2. Add about half a cup of water to the cup. 
3. Add 5-6 drops of food coloring to the water. Stir to mix. (You want a nice dark color).
4. With adult supervision, cut a small piece off the bottom off a stalk of celery to create a flat end. 
5. Place the celery in the colored water with the cut side down and the leaves up. Let it sit for about one hour. During this time, see if you notice any changes.
6. After an hour or so, remove the celery from the water and, with adult supervision, cut a small section about one inch up from the bottom. Lay the celery slice on its side and take a careful look.
7. What do you see? Draw your results on lab worksheet.
8. Return the celery to the colored water and leave for several more hours or overnight. Check back every few hours.
9. Observe the leaves. What do you notice? Draw your results.

What’s happening?

Even though you placed the bottom of the celery into the colored water, you likely noticed that the color moved all the way up the celery, even to the tips of the leaves. How does this happen? How does water move up the celery – apparently defying the laws of gravity?

To answer this question, let’s think about what you did during your experiment. When you looked at the cut slices of celery, you likely saw small round dots of color. The circles are actually cross-sections of a series of long narrow tubes that run lengthwise through the celery stalk. These tubes are called xylem (fun word, right?). Xylem helps to move water from the roots of a plant up to the leaves and flowers. How does this work?

This upward movement of water (or any liquid) is called capillary action. Capillary action happens because of two properties of water:

1. Water molecules like each other so much that they stick together. This stickiness creates surface tension because water molecules are more attracted to each other than they are to the air. We learned about this during Week 2 of Camp Yellow Scope.
2. Although water molecules like to stick together, sometimes they want to stick to other substances even more. In this experiment, the water molecules are more strongly attracted to the xylem tubes in the celery than they are to other water molecules. So they stick to the sides of the tubes and are pulled up. As the surface water molecules move up the tube, they pull along the other water molecules. In this way, water moves up the celery stem.

Capillary action is what allows water to be pulled up the stem of a plant to be delivered to all the different parts of the plant. 

Why does it matter? 

Can you think of examples of capillary action from your daily lives?

1. When you clean up a juice spill with a paper towel, it's capillary action that draws the liquid into the paper towel! 
2. Capillary action helps to move tears across your eyes, clearing away dust  and particles and keeping your eyes clean. 
3. If you want to make the whole bread moist by dunking a small portion in gravy, you need capillary action.

You own it!

Test yourself: Match the Column!

1. A narrow tube that helps to carry water in plants.            a. Capillary action
2. Formation of tears requires...                                       b. Narrow
3. For capillary action to occur, the tube needs to be...         c. Xylem

Answer Key: 1-c, 2-a, 3-b

We hope you had fun learning about the built-in straws in celery. Next week we'll use capillary action to separate colors in dyes! So check back next Tuesday for new experiments and more summer science fun!

We'd love to see how your experiments turned out! Were you able to see the colored dots of xylem in your celery? Share your photos or videos:

• Facebook: Yellow Scope Science Kits for Girls
• Twitter: @YellowScopeGirl, #CampYellowScope
• email: info@yellow-scope.com

For more exciting experiments, check out our science kits on the SHOP tab of our website!