Fourth grade scientists investigated sound. We used tuning forks to feel and hear vibrations. Then we struck the tuning forks and held them on lab tables. The volume of the sound increased, but we could really hear the sound when we placed our ears on the tables. Sound waves (unlike light waves) need to travel through a medium such as a solid, liquid, or gas. The sound waves move through each of these mediums by vibrating the molecules in the matter. The molecules in solids are packed very tightly. The spacing of the molecules enables sound to travel much faster through a solid than a gas (air).
In our next investigation, I swung air tubes. As air spiraled through the tubes, we heard sound. The sound has a higher pitch the faster the tube moves. If the opening is covered preventing air to enter the tube, sound stops. We will each have a chance to use these in our next lab. Click here to learn more.
We wrapped string around our fingers that was attached to a spoon or a hanger. As we hit the objects against different materials around the lab, the sound waves traveled up the string into our ears with surprising results.