Some things you automatically relate to St. Patrick’s Day – hearts, stars, horseshoes, clovers and blue moons, pots of gold and rainbows, and red balloons. Oh wait, that’s Lucky Charms. I must be hungry.
Regardless, many of those items are representative of the Irish holiday. So what better than to have an experiment that’s toddler friendly and creates a pretty rainbow (pot of gold not included)? That’s exactly what the walking water experiment does! The walking water experiment uses the idea of capillary action to create a rainbow effect with colored water and paper towels.
Capillary action is what dyes white daisies when they are placed in colored water. It is the action that causes colored water to travel up stalks of celery. There are so many different examples of capillary action that you can do with your children. Capillary action is the movement of water through porous materials. In these examples and the rainbow themed one below, this includes the movement of colors through these porous materials.
To celebrate St. Patrick’s Day, Little Mister, Little Miss and I invited several of our friends over to participate in the experiment and have a little Irish fun. The kids were so excited about the experiment. They all gathered around the table, pointing at the food dyes and the paper towels. They were patient, taking turns each pouring water into the glasses and then taking turns putting drops of food color in three of the glasses. They would call out the color of the dye and pick the glass it should be dropped into. Then they even helped fold all of the paper towels.
Unfortunately, after we finished the experiment to the step where we wait, all the kids went back to the playroom for some play time. All of the kids except Little Mister. I thought he was just playing in the living room, as he had been when I check on him. Then one of the other moms went into the kitchen… and found Little Mister playing in the water, dunking all the paper towels into the different glasses, mixing all of the colors.
Well, at least he had fun playing in the water and seeing how the colors mixed.
Needless to say, we repeated the experiment later that night and the other kids will never know what happened.
Materials Needed:
- 6 glasses (larger, stable glasses are better to ensure that the paper towels won’t cause them to tip)
- Red, Blue, and Yellow food dye
- 3 cups of water
- 6 sheets of paper towel (If using select-a-sheet, you need 6 sheets. If using full size sheets, only use 3 sheets and then cut them in half to create 6 sheets.)
Experiment Procedure:
1. Pour one cup of water into three of the glasses, leaving the remaining three glasses empty.
2. In each of the three glasses with water, drop 15-20 drops of food coloring, making one glass of water red, one glass of water blue, and one glass of water yellow. It can be helpful to stir the water to ensure the coloring spreads in the water. Make sure that the colors do not mix, though.
3. Fold each of the sheets of paper towel in half, what I used to call hot dog style, and then in half again, so that you get six long sheets of paper towel.
4. Arrange the glasses in a circle so that you alternate a glass with colored water with an empty glass.
5. Place a paper towel in each glass, draping it over the side into the neighboring glass. In the end, each glass with have two ends of paper towel in it.
6. Next wait and watch (and move it out of little playful hands)! It will take 24-48 hours for the water to finish moving and really show the entire rainbow.
So a few takeaways to discuss with your kiddos about this experiment:
- How do they think the water moves through the paper towel? What is surface tension? Is the table wet? Why doesn’t the water fall onto the table as it moves between the glasses?
- What makes the water stop in the glasses? Why doesn’t the water keep moving from glass to glass?
- Where else can we see capillary action? How do plants pull water from the ground? What about when you clean up water from the table? What other examples can they think of?
- What are the colors of the rainbow? How do the primary colors combine to create the secondary colors?
Have fun and enjoy creating the rainbow! I’m going to go have a bowl of Lucky Charms now.