TomWalton

I teach at Kennedy Middle School in Aiken, South Carolina. The course I teach is seventh grade science.

Lesson Title - PROPERTIES OF SOUND

Sound does not travel through a vacuum. Sound must travel through a gas (air), a solid or a liquid. This lesson will demonstrate that sound passes through a solid.

 

Original toy lesson.

Space Phone

Objectives:

-The learner will be able to demonstrate that sound is produced by a vibrating object.

-The learner will be able to conclude that sound does not travel through a vacuum.

-The learner will be able to construct a toy (a space phone) that demonstates that sound can travel through a solid.

-The learner will be able to distinguish the pitch of the sound changing within the same solid.

- The learner will be able to predict the highness or lowness of the pitch when lengths of the space phone are changed.

- The learner will be able to relate the importance of sound and pitch changes in understanding danger signals as well as in appreciating music and other pleasant sounds.

Vocabulary:

- Medium - A medium is matter through which sound waves will move.

- Frequency - Frequency is the number of sound vibrations per second, measured in hertz.

- Pitch - Pitch is the highness or lowness of a sound, depending on the frequency of sound vibrations.

- Longitudinal wave- A logitudinal wave is a regular pattern of pressure changes in which the wave moves in the same direction as the force which caused the vibration.

Materials needed:

- 1 slender Slinky that can stretch to six meters or more

- 2 clean plastic soda bottles

- scissors

- duct tape

Construction:

- Cut the tops off of the plastic soda bottles 3 inches from the pouring holes.

- Fit each end of the Slinky onto each pouring hole end of the plastic soda bottles.

- Secure the Slinky to the plastic bottles with the duct tape.

Directions for use:

- With a partner, stretch the Slinky apart about six meters.

- Have your partner speak into one end of the space phone as you listen in at the other.

- Have a third person twist the Slinky about three times and then release.

- Listen for the variation in the pitch of the sound.

Variations:

- Tap the Slinky three or four times.

- Stretch the Slinky to distances greater or less than six meters and repeat the directions for use.

Explanation:

- By talking into one end of the the conical earphones (plastic soda bottles), the vibrations from the vocal chords make the air in the phone vibrate. These vibrations are transferred to the end of the phone, which in turn vibrate. The same vibrations are traveling along the coil of the Slinky in longitudinal waves, making the bottom of the other earphone vibrate.The air in the receiving earphone is thus reproducing the exact same vibrations, resulting in the voice of the original speaker.

A whisper in the air could not be heard. The waves travel through the solid metal coil to the other earphone, and it is much more facilitated. Sound travels faster and easier through solids than through air.

Because of the coiled nature of the loose spring of the Slinky, the solid metal elongates and shortens from the gravitational pull on the coil. The Slinky is stretched and shortened repeatedly. The sound waves continually move from one end of the coil to the other. By the constant tightening and loosening of the metal coil, different frequencies occur causing the wavering (weird space) sounds in the phone.

 

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  http://rpsec.sc.edu/Classwork/731sp2000/Lesson/waltont/sound.html(March,2000)

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