Musical Glassware

Musical Glassware

“Musical Glassware”

Student Learning Objectives:

  • Correlate pitch with the amount of water a glass holds
  • Connect sound and energy

Materials (per team):4 Identical Drinking Glasses

1 Wood Pencil (or Spoon)

1 Metal Spoon

Water

Introduction:

All materials have a natural frequency, an amount of energy with which they vibrate. When energy is added to a material, the molecules in the material will have a larger vibration. The larger the vibration of an object is in air, the more sound, the more energy the object sends into the air. Increased vibrational energy in an object is called resonance. Increased vibrations may produce compressions in the air (sound) that can be heard.

Waves Transfer Energy

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Preliminary Questions:

A. Do you think the wood pencil or the metal spoon will make the most sound?

B. Which do you predict will produce the highest pitch, the glass with the least amount of water or the glass with the greatest amount of water?

Warning: Broken glass may result in a cut. If you break a glass, do not touch it. Tell your teacher while someone from your team keeps others clear of the broken glass.

Procedures:

Your team will be making glasses sing and testing which device produces the greatest amount of sound.

1. Read all procedures (2-5) before you begin any experimenting. Then carefully read each step as your team completes this activity. Take turns, alternate, using the materials and making observations.

2. Fill each glass with the specified amount of water.

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3. Tap each glass with the wood pencil (or spoon). Observe the water as the glass is tapped. Record which glass produces the highest frequency. You may need to repeat the tapping a couple of times to verify your answer.

4. Tap each glass with the metal spoon. Observe the water as the glass is tapped. Record which glass produces the highest frequency. You may need to repeat the tapping a couple of times to verify your answer.

5. Dip your finger in some water and circle your finger around the lip of each glass. If you circle your finger at a pace that matches the frequency of the vibrating molecules, your glass will sing. Observe the water in the glass while you do this.

6. Add the water from the ¼ full glass of water to the glass that is ¾ full, creating another full glass of water. Set the two full glasses of water near each other on your table. Alternately tap one with the wood pencil (or spoon) and the other with the metal spoon, being careful to tap equally hard on each glass. Record which device transfers the most energy to the glass, which device makes the glass produce the most sound.

7. Clean up:

  • Pour the water onto nearby plants or grass.
  • Completely dry all glassware.
  • Return all materials to their designated place.

Analysis & General Questions:

1) Explain connections between energy and sound that you observed in this experiment.

2) Which device produced the most movement in the water?

  1. Wood Pencil (or spoon)
  2. Metal Spoon
  3. Finger

3) Which device produced the most sound?

  1. Wood Pencil (or spoon)
  2. Metal Spoon
  3. Finger

4) Sketch a model of a sound waves that travels from a drinking glass to your ear.

Ciardi, TMirrors1