Mathematics/Physics

Sound: The Vibration of Materials

Camille Gales	Coles Elementary
	8441 S. Yates Blvd.
	CHICAGO IL 60617
	(773) 535 – 6550

Objective(s):

1. Students will recognize that sound is produced by the vibration of materials. 2. Students will recognize that the sound produced is dependent on the type of material that is used. 3. Given four types of material; air, string, wood, and metal, students will identify air as being the poorest conductor of vibrations, and metal as being the best. 4. Students will recognize that if there is no material to vibrate there will be no sound. These activities are suitable for students in the primary grades.

Materials:

rulers	Tubes	Ticking objects	3 ft. cotton string	3 yds. Thin wire	Vacuum jar
	Rubber bands	1 ft wooden rod	3 ft. thin wire	3 yds. Cotton string	Ticking object
	Thin rubber sheets	1 ft. metal rod	Metal spoon	Cups-paper or styrofoam
	Paper clips

Strategy:

1. Hold the ruler 4 inches over the edge of the desk. Strike it. Observe its movement and listen for its sound. What kind of movement did the free end of the ruler make? What did you hear?
2. Stretch a thin sheet of rubber over each end of the tube. Secure each end with a rubber band. Thump one end of the tube while gently holding your hand over the other end. Feel and observe. What do you feel? What do you hear? Now place a paper clip on the rubber sheeting at one end of the tube. Thump the rubber sheeting at the other end. What do you see? What do you hear?
3. Get 3 ft. of cotton string. Tie the spoon at the center of the string. Wind about 3 inches of string around the forefinger of each hand. Stick those fingers into your ears and strike the desk with the spoon. Observe. What do you hear? Follow the same procedure using 3 ft. of wire. Observe. What did you hear? Compare the two sounds.
4. Get a wind up clock or a timer. Press one end of the wooden rod against your ear; place the other end against the ticking object. Observe. What did you hear? Follow the same procedure using the metal rod. Compare the two sounds.
5. Get 3 yds. of string and two paper cups. Place a small hole in the bottom of each cup. Place each end of the string through the hole in the cup and secure the string by knotting it. With a friend, stretch the string. One person whispers into the end of the cup. The other person places the other cup to the ear and listens. Observe . Follow the same procedure using 3 ft. of thin wire. Observe. Compare the two sounds.
6. Place a ringing alarm clock inside of a vacuum jar. Ask the class what they think will happen when the air is removed from the jar. (The sound of the ringing should fade into silence or close to silence as the air in the jar is removed.)

Performance Assessment:

After students complete activity #1, they should be able to state that they observed the rapid up and down movement of the ruler and that while the up and down movement was taking place sound could be heard.

After students complete activity #2, they should be able to state that they heard a sound when the sheet of rubber was thumped, that they felt movement at the opposite end of the tube, and that the paper clip bounced when they thumped the opposite end of the tube.

After students complete activities #3,4,5, they should hear sounds through the wood, wire, and the string. They should observe the difference in sounds when they are transmitted through the various materials.

After the students observe activity #6, they should be able to state that the reason the sound in the jar is getting softer is because the air in the jar that is being reduced. When all of the air is removed from the jar the students should not be able to hear the ringing. There is no air in the jar for the alarm clock to vibrate and so there is no sound being heard.

Grading Rubric:

A - Student will be able to state that sound is produced because some material is vibrating. Student will be able to demonstrate vibration by doing activities one and two which involve either seeing or feeling the vibrations. Student will conduct activities 3,4, and 5 to demonstrate and explain that the sound which is produced depends on the material through which the vibration occurs. Student will be able to predict that as the air in the vacuum jar is removed the ringing will get softer.

B - Student will be able to state that sound is produced because some material is vibrating. Student will be able to demonstrate vibration by doing activities one and two. Student will be able to demonstrate that the sound produced depends on the material being vibrated by doing two of the following three activities (activities 3,4, or 5). Student will be able to predict that as the air in the vacuum jar is removed the ringing will get softer.

C - Student will be able to state that sound is produced because some material is vibrating. Student should be able to demonstrate vibration by doing activity one or two. Student will be able demonstrate that the sound produced depends on the material being vibrated by doing at least one of the following activities (activities 3,4,5). Student will predict that the sound in the vacuum jar will get softer.

D - Student will be able to state that sound is produced because some material is vibrating. Student will be able to demonstrate vibration by doing activity one. Student will be able to demonstrate that the sound produced depends on the material being vibrated by doing one of the following activities (activities 3,4,5). Student will observe that the sound in the vacuum jar is getting softer.

Conclusions:

Sound is produced when materials vibrate.

The type of sound produced depends on the material through which the vibration occurs.

There can be no sound if there is no material to vibrate.

References:

Physics, VanCleave, Janice. John Wiley & Sons, 1991.

Sounds Experiments, Broekel, Ray, Children’s Press, 1983.

Primarily Physics, Hillen Judith, et.al., AIMS, 1990.