RP: Wavespeed

Question 1

What is the method for investigating wave speed in a solid?

Answer 1

Switch on the vibrator generator
Slide the wooden bridge along until you can see a wave
The wave will look as though it’s not moving.This is called a stationary wave
Then find wavelength

Question 2

How do you find the wavelength in this practical?

Answer 2

First count number of half wavelengths
Then measure the distance across as many half wavelengths as possible
Divide the total length by number of loops to find the length of a half wavelength
Now double it to find the length of one wave

Question 3

What is the practical for measuring wave speed in air?

Answer 3

Get someone to stand a far distance away
Measure the distance
Get the person to make a noise
Time the length of time it takes for the sound to reach you
Divide the distance by the time to get the speed of the sound waves

Question 4

How can you measure the wave speed in a liquid?

Answer 4

First set up the ripple tank
Pour water to a depth of about 5mm into the tank
Adjust the height of the wooden rod so that it just touches the surface of the water
Switch on both the overhead lamp and electric motor
Adjust the speed of the motor.Low frequency water waves need to be produced
Adjust the height of the lamp so the pattern is clearly seen
Place the ruler perpendicular to the waves shown in the pattern on the card
Measure across as many waves as possible then divide that length by the number of waves giving you the wavelength
Count the number of waves passing a certain point over a given time
And calculate frequency
Then calculate wave speed

Question 5

What is important in the practical for measuring wave speed in a liquid?

Answer 5

The ruler is perpendicular to the waves

Question 6

What’s the advantage of repeating measurements and calculating means?

Answer 6

Can eliminate any anomalies