VIBRATIONS AND SOUND

I love teaching sounds and vibrations but forget year to year how four hours of sounds a day can lead to a raging headache. Thanks to Motrin for getting me through the week. I didn't read the students a book as I usually begin class but instead downloaded an app for my IPhone called "100 Sounds". We talked about all of the sounds we learn and store in our brain. I then played about 20 sounds easy and hard and let the kids guess. They were very good at it and enjoyed it a lot. I began with sound being energy and that energy doesn't take up space. You can't blow up a balloon by placing it in front of a speaker and turning up the volume. Sound is energy like light and they don't take up space or aren't make of atoms and molecules. We compared sound and light. Light travels in straight lines. I shined a flashlight on a child and we noticed that it only reflected on the one person, the others were in the dark. Sound however travels in all directions in circle like a rock landing in a pond and making waves in all direction. Sound is faster in solids, then liquids and slowest in the air. Light is the opposite and is fastest in the air. Sound has to have matter to move. If you were on the moon and screamed there would be no sound because there's no air for it to travel through. Light however would be the fasted with no air. Light is much faster that sound and in a race light would travel around the earth in 1 second, sound would take 36 hours. People can't travel the speed of light but we can travel the speed of sound in a jet. I asked where sound would be faster, cold air or warm air? Cold air because the molecules are closer together.

Next we looked at sound waves. I made these out of rope. First I made a fast wave with the waves very close together and told them that this was a high frequency sound and we all made high sounds. Then I showed them waves far apart and we made low sounds. Next we made big waves these are loud sounds and small waves are soft sounds. People can hear sounds between 20 and 20,000 Hz. One hertz is one wave per second. Dolphins can hear at 200,000, bats at 120,000 and dogs at 80,000. Elephants can hear down to 8 hertz. I downloaded a free tone generator online and played low tones to high tones to see what the kids could hear. I used a tuning fork and placed it in water so they could see the effect of the vibrations. I then touched it to the kids noses so they could feel the vibrations.

Next I moved on to how the ear works. After showing them a picture of the inside of the ear I lined 3 kids shoulder to shoulder and told them they were the hammer, anvil and stirrup. I pretended to be a ear drum. I started vibrating and whacked into the "3 little bones" and they all crashed into each other. This stimulated the cochlea and a message is sent to the brain.

I then made sounds with a singing rod, running my finger around a piece of crystal, and cup with a sting through it with a sponge on the end. We finished with the wax paper around a comb and putting bolts in a balloon and having the kids spinning them to make vibration sounds. Each kid received a wooden slide whistle to decorate and take home.