8.2 Pitch and frequency
8.2 Pitch and frequency
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Slide 1: Slide
Natuurkunde / ScheikundeMiddelbare schoolhavo, vwoLeerjaar 2
This lesson contains 18 slides, with text slides and 1 video.
Lesson duration is: 45 minItems in this lesson
8.2 Pitch and frequency
Slide 1 - Slide
Schedule for this lesson
Explanation the period and frequency of a vibration
Playing a game with the exercises
Slide 2 - Slide
Learning objectives 1/2
-You can write down three factors that affect how high the tone is that a string produces
- You can explain what the frequency of a vibration is
- You can determine the vibration period of a tone in an oscilloscope trace
- You can do calculations using the vibration period and frequency
Slide 3 - Slide
Learning objectives 2/2
-You can give the frequency range of human hearing
Slide 4 - Slide
The vibration period and frequency
When a sound is made a vibration is given off
We can see these vibrations in so called oscilloscopes
Slide 5 - Slide
The vibration period and frequency
Each square on the oscilloscope gives an amount of time
(1 square is 0,5ms)
And each vibration takes a certain
amount of time to complete
Slide 6 - Slide
The vibration period and frequency
The vibration period is the amount of time it takes to complete 1 full vibration
In this picture we see multiple vibrations, at which point(s) do we see a completed vibration?
Slide 7 - Slide
The vibration period and frequency
With the time 1 square takes up, and the amount of completed vibrations we can calculte the vibration period (T)
For example, we have
3 completed vibrations
What is the time for these 3 vibrations?
Slide 8 - Slide
The vibration period and frequency
We divide the time it takes to complete a certain amount of vibrations with the amount of vibrations and we get the vibration period (T)
T = 2,4/3=0,8ms = 0,0008
Slide 9 - Slide
The vibration period and frequency
If we know the period of a vibration we can calculate its frequency (f) in Hertz (Hz)
We can do this with the formula
f = 1/T
Slide 10 - Slide
The vibration period and frequency
The frequency means the amount of vibrations that happen over 1 second
For example, if the vibration period is 0,1 s, there are 10 vibrations in 1 s
1/0,1=10
Slide 11 - Slide
The vibration period and frequency
When we calculated T we got the answer of 0,8ms
Now we can calculate the frequency
f=1/0,0008=1250Hz
Which means 1250 vibrations per second
Slide 12 - Slide
The vibration period and frequency
Calculate f with a vibration period of...
0,004ms
39ms
and with 0,011
Slide 13 - Slide
The vibration period and frequency
We humans are able to hear sounds with low and high frequencies
Our hearing range is between 20hz and 20000hz
We can visualize these sounds with a video
Slide 14 - Slide
Slide 15 - Video
Playing a game with the exercises
I have an excel sheet in which i can give points to a team
The amount of point you can get is different each exercise (and is shown on the sheet)
For the rest of the lesson you will make these exercises on a piece of paper, when you are done with 1 exercise you come to me and I will check it
Slide 16 - Slide
Playing a game with the exercises
When you are correct you will go to the next exercise and you get all points
When you are incorrect you will lose a point, but if you correct the mistake you can still earn a few points. If you are correct after correcting the mistake you will go to the next exercise
Slide 17 - Slide
End of the lesson
