You know that teacher moment when everybody goes quiet? And you either think to yourself, “I am winning life,” and feel like a million dollars OR, if you’re like me, you think, “Oh no, what is happening? What’s gone wrong?” This investigation is one that usually falls in the first camp. It’s cooperative, quiet and fascinating.
Wire coat hanger, string, scissors, someone to investigate with
Where to start
Cut two lengths of string and tie them to each side of the coat hanger. Then, form a loop on the other end of each string and you have made a musical instrument. Slip the loops over the ends of your fingers and ask someone else to hit the coat hanger with a pen or a stick. Tell them first that this is in the name of science, otherwise they might think you’re a bit strange. It doesn’t make a very loud sound. Now, still with the loops over your fingers, put your fingers in your ears and hit the coat hanger again. You may have to lean forward slightly to stop the coat hanger touching your tummy.
What’s the STEM?
For sound to travel from one place to another, it needs something to move through. On Earth, air allows sound waves to move from one point to another. Sound can also move through water and the coat hanger is also useful for investigating how whales and dolphins communicate over such long distances. Sound waves travel through vibrations, which means that the atoms or molecules need to touch each other to move the vibrations on. However, space is mostly a vacuum. Although there are some atoms floating around, they are VERY far apart, which means that there is no sound on the Moon. Unless you’ve got someone saying in your earpiece, “Houston, we have a problem.”
Observations, conclusions and extensions
A good way to explain how the vibrations travel through air or the coat hanger strings is to ask the children to stand very close together and one child wiggles. They will all feel the wiggle. Then, ask them to spread out and wiggle – can they feel anyone else?
You can check the prior knowledge of the children. What do you need to be able to breathe in space? Why? Do they know what a vacuum is? You could pretend to be air molecules and water molecules through movement and dance.
Use your explorations to introduce this STEM vocabulary to the children:
vibrations, strike, material, plastic, metal, sound, volume, quiet, loud, propagate.