Science projects have long been an educational rite of passage for students. They are often the first experience students have to develop, enact, and explain an experiment in critical thinking terms. For elementary students, there are a number of fun sound wave science fair projects for those who are interested in the way sound travels.
Build a Telephone
Using two hard plastic or tin containers, like cottage cheese or coffee cans, poke a small hole in the bottom and thread 4 inches of the end of a 10- to 15-foot piece of string through each hole. Tie a knot on the length of rope inside each of the cans so that the string does not slip through the opening. Stretch out as far as you can, leaving a little slack in the string. Say something into the open end of your can. The string should pick up the vibration of what you are saying, and if your partner with the other can has it up to his ear, he can hear what you are saying clearly. Experiment with different string lengths, volumes, and can types to see how they compare.
Fill 8 empty glass bottles of similar make and size with water, starting small and adding a slight amount more each time. The amount of air in the bottle will affect the sound it makes. Blow into the bottles or clink them with a spoon. If there is only a small amount of water in the bottle, it will produce a higher tone; if there is more water in the bottle, it will make a lower tone. Experiment with different bottles, sizes, and water amounts to see what type of sounds you can make.
Sound Wave Model
Using 6 to 8 pieces of 10-inch thread, attach a metal ball bearing to the end of each using a piece of tape. Tie all the strings 1 to 2 inches apart on a coat hanger or thin rod. Pull the leftmost ball bearing away from the others and let it go. Watch it collide with the second ball bearing, which hits the third, and so on. This is a model of how sound models interact with each other: they vibrate and ram into each other, one step at a time, as the sound travels further and further away.