Required Practical 08.1: Ripple Tank

Question 1

How do you use a ripple tank before measuring wave length, frequency and wave speed?

• depth; paper
• wood
• turn on
• adjust
• adjust

Answer 1

1. Set up and fill the ripple tank so the water has a depth of ~5mm, placing white paper or card under it.
2. Place a wooden bar on the water surface.
3. switch on the overhead lamp and the motor.
4. adjust speed of motor so low frequency waves are produced.
5. Adjust the lamp so that the pattern can be seen on the paper.

Question 2

How do you calculate the wave length?

• ruler
• wavefronts; waves

Answer 2

1. Place the metre ruler perpendicular to the wavefronts on the page.
2. Measure the length across as many wavefronts as possible and divide by the number of waves.

Question 3

How do you calculate the frequency?

• specific point

Answer 3

1. Count the number of waves passing a particular point in the wave tank over a given time (measure 10 or 20 seconds using a stop clock).

Question 4

How do you calculate the wave speed?

• equation
  OR
• (unrelated) equation

Answer 4

Use the equation: wave speed = wavelength × frequency.
OR
Calculate the distance travelled by one selected wave to length of tank divided by time taken.

Question 5

Why might you get various results measuring wave speed using both methods?

Answer 5

Measuring errors (timers)