A Glass Symphony
Grade Level: 4th-6th Type: Physical Science
Students will discover whether different amounts of water added into a wine glass will produce a different pitch when their fingers are rubbed along the rim.
- How do our ears help us hear?
- Does the size of the object matter in terms of vibration and pitch?
The things around us all have a natural sound frequency that causes it to vibrate which is called resonant frequency. When you force energy onto a material, you will cause it to vibrate and the vibrations will travel through the material and into the air molecules. As it travels through the air molecules, sound waves are produced and that is the sounds that we hear with our ears as the soundwaves are sent to the brain.
- Wine glasses (the ones with the thin rims work better)
- Do not fill this wine glass with any water. Hold the glass in place with one hand at the base and simply wet your finger and lightly rub against the rim of the wine glass. What do you hear?
- Now fill the glass about ¼ full with water. What has happened to the sound?
- Now fill the glass about ½ full with water.
- If you have a larger or small glass, try to see what happens to the pitches in these glasses. Are they the same as the first glass?
- Record your findings.
Terms/Concepts: Sounds waves; resonant frequency; hearing
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