Tin Drums (Science Component of Rhythm and Sound ) by S. Boshoven
Objectives : To investigate sound and resonance.
Materials: tin cans of different sizes, balloons or rubber gloves, rubber bands, string, fishing line, thin wire, journals, pencils.
Time: 4 to 6 hours.
Preparation of drums : Cut the top and bottom off of tin cans of different sizes. Stretch a piece of balloon, punch ball, or rubber glove over one end of each can and fasten it with a rubber band. Use pencils with large erasers or a ball of rubber bands on the end as drum sticks.
Experiment I Play the drums, comparing and writing observations of the sound that a large can makes as opposed to a small can, a tall can as opposed to a short can, or fat can as opposed to a thin can. Put two cans together to form a longer can. Substantiate your observations by making measurements, organizing the data, and comparing it with a companion.
Experiment II Choose cans which resonate well (sustain a tone the longest). Experiment with how the thickness of the skin affects the sound of the drum.(for more notes on this go to Sound Quality of Hide Skin Drums ) Find pieces of rubber of different thicknesses. Balloons, punch balls, rubber gloves work well as drum skins. Stretch them on same size tin cans. Again, compare the sounds. Experiment by tightening and loosening the skins to tune the skin so it resonates with the can. If you have tuning forks, find the resonance of different drum chambers (or cylinders of any material) by trying different vibrating tuning forks over them until they hold the tone.
Experiment III Make telephones with different types of cords (wire, string, or fishing line) and paper cups or cans, and compare how the sound of the telephone changes depending on the type of cord used to connect the cups or how tight the cord is pulled. With one cup and a string attached you can hear how the tone of the string changes with the length. Place the cup over your ear, pull the string tight and pluck it. Note the sound and then extend, or shorten the distance you are pulling the string and pluck it. Note the difference in the sound.
Extended Activities and Links:
Arrange a group of different length cans or jars with the same diameter from low tone to high tone forming a scale.
Study of frequency and harmonics with an oscilloscope, for example, or tuning forks. Experiment with determing scales mathematically.
Making flutes with tubes of different size. (Use test tubes with different amounts of water in them or cut bamboo to different lengths.)
Invent or construct a string instrument.
Invent a device to measure the frequency of a sound vibration.
Make a model the ear drum.
See Exploratorium snacks related to resonance.