Ever wonder how your voice carries across a room? Make a sound wave model to mimic the movement of air molecules when carrying sound. You may be surprised to find that it takes a lot more than just a strong set of lungs to be heard.
What You'll Need:
- Six metal ball bearings
- Clothes hanger
Step 1: Cut six pieces of thread, each 10 inches long, and attach an end of each thread to a ball bearing using tape.
Step 2: Tie the other end of each thread to the horizontal piece of a clothes hanger, leaving about one inch between each thread that you tie. Hang the hook of the clothes hanger from a shower-curtain rod.
Step 3: Pull back one of the end bearings. Let the bearing go so that it strikes the next one. Watch what happens. It hits the second, which swings and hits the third, and so on.
Sound travels through the air in the same way. A vibration causes one molecule of air to move and bump into another molecule, which then moves at the same rate and bumps into a third molecule, and so on.
Go to the next page to learn how sound travels through a simple telephone.