Practical

Question 1

Water waves in a ripple tank

Answer 1

1. Fill the ripple tank so the water has a depth of approximately 5mm. Place the ripple tank on top of a piece of white paper or card.
2. Place a wooden rod on the surface of the water and attach it to the low-voltage power supply and motor. Add a lamp to the circuit and hold the lamp above the ripple tank.
3. View the wave pattern from the side of the tank, looking through the water.
4. To measure the wavelength, place the metre ruler perpendicular to the wavefronts on the page. Measure across as many wavefronts as possible and divide by the number of waves.
5. To measure the frequency, 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).
6. To calculate the wave speed, multiply the wavelength by the frequency.

Question 2

Standing wave on virbrating spring

Answer 2

1. Produce a standing wave on the vibrating string by adjusting the frequency or the generator, the position of the wooden bridge and the tension in the string (by adding or removing masses). A standing wave is created when the wave doesn’t appear to move horizontally, instead the string appears to oscillate only vertically.
2. To measure the wavelength, use a metre ruler to measure across multiple standing waves and divide by the number of total waves.
3. To measure the frequency, use a stopwatch to time wave oscillations over ten complete cycles. If the wave is slow enough, time the point at the centre of the half-wavelength, starting at equilibrium and counting every other time the string passes the equilibrium as a complete cycle. Divide this value by 10 to find the time period. Then use the equation, to find the frequency

Question 3

Leslie cube

Answer 3

Align the infrared detector with one side of the Leslie Cube, 20cm away from the side, and take the initial temperature of the surface.
2. Heat one side of the Leslie Cube by pouring hot water onto the surface.
3. Measure and record the temperature of the surface every 30s for five minutes.
4. Rotate the cube and repeat the experiment for a different surface.
5. Plot temperature (plot on y-axis, measured in °C) against time (plot on x-axis, measured in seconds) for each different surface.

Question 4

Acceleration

Answer 4

1. Draw a series of straight lines, each 20 cm apart, perpendicular to the edge of the bench.
2. Attach the car to the string at one end, with the other end running across the bench pulley.
3. Attach the weight stand to the loose end of string (you may need to tie a knot at that end, to hook the stand onto). Hold the weight of the pulley, so it doesn’t pull the car but so that the string is fully extended.
4. Release the weight stand (allowing it to fall) and begin the timer. Stop timing when the car hits the pulley at the other end of the bench.

Question 5

Hooks law practical

Answer 5

Set up your equipment, ensuring the spring will return to its original dimensions if stretched within its elastic limit.
2. Attach the pointer to the base of the spring, ensuring that it isn’t angled (parallel to the workbench) and perpendicular to the metre ruler. Align the top of the ruler with the top of the spring.
3. Measure the initial length of the spring without any weights attached.
4. Add a 10g mass to the base of the spring and record the length of the spring.
5. Repeat and continue to add masses, ensuring that the spring doesn’t oscillate after each weight has been added.
6. Calculate the extension of the spring for each mass by subtracting the initial length of the spring from each different length of the spring.
7. Convert all masses to weights using the equation:
Weight (N) = mass (kg) x 9.81 (N/kg)
8. Plot the graph of force (y-axis) against extension (x-axis). Calculate the gradient.