Luck of the Irish: St. Patrick’s Day Science

St. Paddy's Science - Capillary Action Shamrocks
Published: Mar. 17, 2022 at 7:21 AM EDT
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GREENVILLE, N.C. (WITN) - You can feel the luck of the Irish this St. Patrick’s Day with some festive, at-home science experiments.

From rainbows, to pots o’ gold and shamrocks, Ms. Covey Denton and her daughters, Bethany and Lydia, presented St. Patrick’s Day themed experiments on WITN News at Sunrise Thursday that you can recreate at home to get into the holiday spirit.

Be sure to watch the attached videos!

Descriptions from Ms. Denton:

Capillary Action Shamrocks

To do this experiment, cut out a shamrock from construction paper. If you want to write a message, use a sharpie marker in the center. Carefully fold in the petals of the shamrock and place in a shallow pan of water. As your shamrock floats, the petals start to unfold. Paper is made from fibers from plants. These fibers can absorb water through a process called capillary action. When the giver absorbs, it swells up and pushes the shamrock open. You can try this with other types of paper too! How would tissue paper work? Paper towel?

Capillary action is the movement of a liquid through another material despite other forces, such as gravity. Plants use capillary action to get water from their roots up to the top of the plant. Paper towels use capillary action when we use them to absorb sipps in the kitchen. Even nurses use capillary action when they use a small glass straw to draw up blood from a finger-prick!

Grow a Rainbow

In our first experiment, you say that capillary action could make our shamrocks open, now let’s use capillary action and our knowledge of solubility to grow a rainbow!

To do this experiment, take a paper towel and use water-soluble markers to draw a rainbow pattern on the end. Place the end in water and watch as the capillary action moves the water up into the paper towel against gravity. Because washable markers are water-soluble, the water pulls the ink along with it. If you were to replace the washable markers with permanent markers, the ink wouldn’t move much at all. That is because permanent markers use inks that are soluble in alcohol, but not water. To grow a rainbow with a sharpie marker, you would need to fill the glass with rubbing alcohol.

Magic Revealing Rainbow Centerpiece

For this experiment, we used a super absorbent polymer. Many people know these as Orbeez, but we got them from a plant supply store for much less. They are clear polymer beads that can absorb over 200 times their mass in water! That is a lot of water! When they are fully expanded, they are over 99% water. When there isn’t any water in the jar, it is really easy to see the beads. They bend, or refract, light differently than air so they are very easy to see. When you pour the water in, they seem to disappear! This is because they refract the light the same way water does. If you use colored water, the colored beads will bend the light the same way as colored water, so you can make a magic appearing/disappearing rainbow. Our favorite way to do this is to make interactive centerpieces. You can hide little plastic toys in the gel balls and you can’t see them clearly. When you pour water in, they seem to magically appear.

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