Wire clothes hangers are used for a variety crafts and experiments, but for this experiment a plastic hanger will suffice.
If you have already made a switch to plastic for your children's clothes hangers, then this is a great exercise that will not damage a good hanger and will encourage a fascination with science.
By following these instructions, a classroom or just a parent and child can touch on the basic principles of sound production while also using a little creativity.
Gathering the materials can be a fun for the kids, or they can be collected ahead of time (depending on time and the number of children).
You will need a clean, strong rubber band, some glue, a plastic clothes hanger, some thread, and a dozen or so pieces of dry puff cereal like Captain Crunch or Cocoa Puffs.
If your kids have a favorite cereal, use that one and the activity can double as a little snack.
Take the thread and cut a dozen pieces of about twelve inches in length.
If your kids are doing the cutting, it is a good idea to have one piece already cut for them to compare with, rather than needing to measure each piece.
After all of the thread is cut, glue the pieces of cereal to one end of the each piece.
You may try tying the pieces as well, but this may be difficult depending on the type of cereal.
Tying the pieces might also make the lengths of thread more uneven, and the experiment works better with equal lengths.
Next, you should tie the other end of thread pieces to the bottom bar of the hanger.
Once all of the pieces have been tied, hang the hanger on a stable object such as a chair back, closet rod, or table.
Slide the different pieces of thread up and down the hanger so that the cereal pieces are hanging at equal distance from each other.
The closer they are, the better, but there should still be some space between each one.
Give the cereal a few moments to hang freely so that it becomes motionless, and get ready with the rubber band to perform the experiment.
The rubber band should be clenched between the teeth and stretched down with one hand.
A child can then gently pluck the rubber band with the other hand, similar to an upright bass.
It is important not to bite the rubber band to hard, or to stretch the rubber band too much.
This can be done by done by an adult instead, or one child can hold the outstretched rubber band while another one plucks.
The experiment will still work without using teeth, but the vibration is greater due to the solid surface of the teeth.
Continue to pluck the rubber band near the center of the formation of cereal puffs.
As the rubber band is plucked, it vibrates.
This can be observed on the rubber band, but as you continue, the cereal pieces also begin to move.
As the nearest piece of cereal moves more, the other pieces nearest begin to do the same.
None of these things are touching, and there is no force that can be seen, yet the vibration of the rubber band is causing the cereal to move.
The vibrating rubber band is producing sound waves in the air, which affect the cereal puffs.
All sounds are made up of these invisible vibrations traveling through air, liquid, or solids and reaching our ear drum.
Much like the pieces of cereal, our ear drum and the small hairs inside our ear are also moved by vibrations.
Our brain then calculates the speed and strength of the vibrations to help us understand what is causing the vibration, and that is how we perceive sound.
Sounds are simply creations of our brain, telling us the kinds of vibrations that are coming into our ears.
The world is full of complicated vibrations of every type that create the many amazing sounds we hear every day, and this little experiment with a clothes hanger will help kids understand a little more about where sound really comes from.