Try this fun STEM activity to help your kids learn about surface tension, water striders, and physics. They will love getting creative and playing with water!
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I love experiments and STEM activity books. They are a great way to teach science and to develop independent learners. My bookshelves are full of them! Some of my books are broad-based and general. Others have specific themes, like astronomy, nature, water, magnets, air, physics, chemistry, or electricity. One of my favorite series of books is the Tabletop Scientist series from Dover Publishing.
They are colorful books with easy-to-understand science lessons with an experiment or STEM activity to reinforce each one. One of our favorite science projects came from The Science Of Water title in the series. It is a fun water strider STEM activity that lets the kids get creative while teaching them a sometimes hard-to conceptualize scientific concept.
Make Your Own Water Strider STEM Activity
Have you ever seen water striders on a pond? Belonging to the family Gerridae, water striders are one of 350 insect species that literally walk on water. How do they do it and not sink? Check out this short video to learn more about water striders. Then, let’s do a fun water strider STEM activity.
Now, let’s get started. Use these simple instructions to make your own water strider, and learn more about how they accomplish walking on water.
Cut a strip of aluminum foil and wrap it around a paperclip to form a rectangle.
Next, cut two V-shaped notches on each side of the paper clip. Now, you have six sections of foil that will become the legs of your water strider.
Fold the sections down and form legs and feet that can rest flat on a surface all at one time.
You will need a bowl full of water for the next part of this activity. This will be the water your water strider walks on!
Slowly, lower your water strider onto the surface of the water without letting any of the legs go under the water. This may take a little practice, but you can do it. Keep trying until your water strider is resting on top of the water with none of it under the surface.
Notice that the water strider isn’t floating with part of it submerged. It is actually on top of the water. Look and you can see the little dimples in the surface of the water around the legs. It’s like the water has skin.
The Science Of Walking On Water
So how does this work? How can a paper clip wrapped in foil stay above the surface of the water and not sink, when we know that both will sink in water on their own? Go ahead. Throw some foil and a paper clip into the water and see what happens.
Water molecules are polar and like to stick together. On the surface where the water meets the air, water molecules cling even more tightly to each other. This causes a “skin” to form on the surface of the water. This skin is so strong that it can hold a weight that normally would sink in water. This is called surface tension.
The water striders have the unique ability to distribute their weight onto their long legs in a way that the surface tension of the water is strong enough to hold them up. This is the idea that was used in creating the foil water strider. Distribute the weight so there is not one specific spot that is heavier than the surface tension can hold.