Chapter Graphic
 : String Ping
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  Level: Year 4 and year 8
Approach: One to one 
Focus: Predict, demonstrate and report the influence of the length and tension of a vibrating string on the sound produced.
204k
Resources: Spoon with piece of string attached, video showing how to use this apparatus to make sounds.

Questions / instructions:
Put the spoon and string on the table.
In this activity you are going to use a spoon and a piece of string to make different sounds. Let's watch the video to see what to do.
Play video.
Before you try the activity I will ask you some questions.

     
% responses
y4
y8
1. What might happen to the sound when the length of the string is changed?
Prompt: How might the length of the string change the sound?
longer string —> lower pitch
19
34
length affects pitch in unspecified way
30
28
2. What might happen to the sound when the tightness of the string is changed?
Prompt: In what way might the sound change?
no sound at all when string is loose
39
40
tighter string —> higher pitch
10
20
tightness affects pitch in unspecified way
11
13
Let's try these things. Start by holding the spoon to your ear.
What happens when you make the string shorter and then longer?
Allow time.
a
a
   
3. What did you notice about the sound as the length of the string was changed?
Prompt: Why do you think the sound was different?
longer string —> lower pitch
28
53
length affects pitch in unspecified way
28
21
Now try making the string looser and the tighter.
Allow time.
a
a
   
4. What did you notice about the sound as the tightness of the string was changed?
Prompt: Why do you think the sound was different?
no sound at all when string is loose
68
65
tighter string —> higher pitch
11
22
tightness affects pitch in unspecified way
9
9
Commentary:
There were two difficulties with this task. Holding a spoon alongside an ear was seen as inappropriate by a few Mäori children, and the video demonstration showed the string loose for the start of question 4. These limit the usefulness of the results, but year 8 students clearly understood the key relationship somewhat better than year 4 students.
 
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