Sound Waves - Discovery Education

Brief Constructed Response
Sound Waves
Teacher Guide
Unit: Sound, Heat, and Light
Topic: Sound
Concept: Sound Waves
Objectives assessed: The student will be able to demonstrate understanding that:
• Sound is energy that travels in the form of waves away from a vibrating object.
• Sound waves travel through all three states of matter.
• Sound waves cannot travel through a vacuum, which has no matter.
Students will need about 15–20 minutes to complete this brief constructed response.
A scientist puts a bell inside a sealed glass jar. She makes the bell vibrate. Then, she sucks all the
air out of the jar with a vacuum pump. She makes the bell vibrate again. Describe what the scientist
probably heard when she made the bell vibrate each time. Explain your answer.
Sample correct response(s):
At first, the scientist probably heard the ringing of the bell. The vibrations of the bell produced sound
waves, which traveled through the air in the jar, through the jar, and then through the air outside the
jar to the scientist's ears. After the scientist removed the air from the jar, she probably did not hear
the ringing of the bell. She would not be able to hear the ringing of the bell because there was no air
in the jar for the sound waves to travel through.
Note: It is also correct for the student to state that the ringing of the bell was fainter or quieter after
the air was removed, and explain that the sound waves could travel only through the bell and the
glass in the jar before getting to the air outside, so the bell sounded quieter.
Brief Constructed Response: Sound Waves © 2008 Discovery Communications, LLC Page 1 of 2

Brief Constructed Response
Sound Waves
Teacher Guide
Response scoring tool:
Score Content
3 Response includes all of the following: statement that the scientist
would hear the ringing of the bell when there is air in the jar;
statement that the scientist would not hear the ringing of the bell
(or would hear a quieter ringing) when the air is removed from the
jar; and explanation that sound travels through the air in the jar in
the first case but cannot travel through the vacuum in the jar in the
second case.
2 Response includes two of the following: statement that the
scientist would hear the ringing of the bell when there is air in the
jar; statement that the scientist would not hear the ringing of the
bell (or would hear a quieter ringing) when the air is removed from
the jar; and explanation that sound travels through the air in the
jar in the first case but cannot travel through the vacuum in the jar
in the second case.
1 Response includes one of the following: statement that the
scientist would hear the ringing of the bell when there is air in the
jar; statement that the scientist would not hear the ringing of the
bell (or would hear a quieter ringing) when the air is removed from
the jar; and explanation that sound travels through the air in the
jar in the first case but cannot travel through the vacuum in the jar
in the second case.
0 No response, or response not appropriate to the question.
For students who are not demonstrating complete mastery of this concept, the Discovery
Education Science video, reading, and interactive resources found in the Learn and Explore
sections of this concept can be assigned to them as remediation.
Brief Constructed Response: Sound Waves © 2008 Discovery Communications, LLC Page 2 of 2