Required Practicals

Question 1

How would you determine the specific heat capacity of a material?

Answer 1

1. Place a thermometer and an immersion heater into the material you’re experimenting on (into holes if it’s a solid). Make sure you know the mass
2. Wrap the material/its container in insulating foam to prevent loss of heat to the surroundings
3. Measure the temperature
4. Connect a joulemeter and a power supply to the immersion heater
5. Turn on the power supply and wait for 10 minutes
6. Record the temperature every minute
7. Turn off the heater and record the reading on the joulemeter
8. Record the highest temperature reached
9. Calculate the temperature rise and use the equation to work out the SHC

Question 2

How would you investigate the effectiveness of different materials as thermal insulators?

Answer 2

1. Select a range of materials to use as insulators
2. Wrap one of the materials around the outside of a metal or glass container (not under the bottom of the container as this could cause it to tip over)
3. Pour hot water into the container
4. Put a piece of cardboard with a hole in it over the beaker as a lid, and put a thermometer into the hole
5. Record the starting temperature of the water and start the stopwatch
6. Record the temperature of the water every 5 minutes for 20 minutes
7. Repeat steps 1-6 with a different insulator each time

Question 3

How would you investigate how changing the length of the wire affects its resistance?

Answer 3

1. Connect the circuit as shown in the diagram below (C = crocodile clips):
   _____[1.5 V CELL]_____
   |……………………………..|
   (A)…………………………..|
   |__________(V)________|
   |……………………………..|
   |……………………………..|
   (C)ruler with wire(C)

Use insulating tape to stick the connecting wire to the metre ruler
2. Connect the crocodile clips to the resistance wire, 100 centimetres (cm) apart
3. Record the reading on the ammeter and on the voltmeter. Do not allow the current to increase above 1A
4. Repeat the previous steps reducing the length of the wire by 10cm each time down to a minimum length of 10cm
5. Use the results to calculate the resistance of each length of wire by using R = V/I

Question 4

How would you investigate the I-V characteristic of a circuit component?

Answer 4

1. Set up a circuit with four 1.5V cells in series, an ammeter, a variable resistor and the component you’re testing. Add a voltmeter in parallel around the component
2. Adjust the variable resistor to give a pD of 1V across the component
3. Obtain a set of I-V values for -10V to 10V (reverse the direction of the current to get negative pD values)
4. Plot these results. If current and voltage are in direct proportion, the component is an ohmic resistor

Question 5

How would you calculate the density of a liquid?

Answer 5

1. Use a balance to measure the mass of an empty 100ml measuring cylinder
2. Take the measuring cylinder off the balance and place 20ml of liquid into it
3. Place it back on the balance and use the new mass to calculate the mass of water added
4. Repeat and use d = m/v to calculate density

Question 6

How would you calculate the density of regular solid?

Answer 6

1. Use the dimensions to calculate the volume
2. Measure the mass
3. Use d = m/v to calculate the density

Question 7

How would you calculate the density of an irregularly shaped solid?

Answer 7

1. Ensure that the object fits into the measuring cylinder
2. Measure the mass of the object
3. Put enough water into the cylinder to submerge the object and record the volume of water
4. Add the object and measure the new water level
5. Use d = m/v to calculate the density

Question 8

How would you investigate the relationship between force and the extension of a spring?

Answer 8

1. Set up a retort stand, metre ruler and spring. Make sure that the metre ruler is vertical and wear safety glasses
2. Measure the position of the bottom of the spring on the metre ruler
3. Hang 100g weights on the end of the spring. Every time you hang a new weight, calculate the extension of the spring relative to the neutral position
4. Plot the data on a graph

Question 9

How would you investigate the relationship between force and acceleration?

Answer 9

1. On a table, set up a pulley, and a light gate connected to a timer. Attach a trolley with a piece of card on it to the pulley
2. Hold the trolley 0.5 metres from the light gate and add a 100g mass to the end of the trolley hanging off the table
3. Let go of the trolley and use a stopwatch to time how long the trolley takes to get to the light gate
4. Write down the time taken for the card to pass through the light gate
5. Repeat Steps 2-4 until 500g of weight is added
6. Calculate the acceleration with A = L/PR and plot a graph
   A = acceleration
   L = length of card
   P = time taken to pass through the light gate
   R = time taken to reach the light gate

Question 10

How would you investigate waves in a ripple tank?

Answer 10

1. Set up a wave generator in a ripple tank with a lamp shining above it
2. Pour enough water in to fill the tank to a depth of 5-6mm
3. Adjust the wooden bar up or down so that it just touches the surface of the water
4. Switch on the lamp and electric motor
5. Adjust the speed of the motor so low-frequency waves are produced. Make sure you can see the pattern of the waves on the floor
6. Use a meter ruler to calculate the wavelength of each wave
7. Count the number of waves passing a point in 10 seconds and calculate frequency by dividing this by 10
8. Use wavelength and frequency values to calculate wave speed

Question 11

How would you investigate the emission of infrared radiation by different surfaces?

Answer 11

1. Place a Leslie cube onto a heat proof mat. A Leslie cube is a hollow cube with sides of different colours and textures
2. Fill the cube with very hot water and replace the lid of the cube
3. Hold an infrared sensor close to one of the sides, wait for the reading to settle and then record it
4. Take a reading from all 4 sides of the cube. Make sure that the detector is always the same distance from the cube
   Note: If a Leslie cube is not available you can use beakers covered in different materials

Question 12

How would you investigate waves in a stretched spring?

Answer 12

1. On a table, connect a vibration generator to a string with weights on the end. Attach the string to a pulley and let the weights hang off the end of the table. Place a wooden bridge between the vibration generator and the pulley wheel
2. Turn on the vibration generator and move the bridge or add more weights until you can see clear wave patterns in the string
3. Count the number of loops and measure the length of the vibrating string and use this to calculate wavelength and wave speed

Question 13

How would you investigate the reflection of light?

Answer 13

1. Using a support, stand a plane mirror upright on a sheet of paper
2. Draw a line across the base of the mirror
3. Use a ray box with a single slit to shine a narrow beam of light towards the mirror (this is the incident ray)
4. Mark the positions of both the incident and reflected rays by drawing dots
5. Remove the mirror and trace the path taken by the light
6. Draw the normal line and use a protractor to determine the angles of incidence and reflection
7. Record your results in a table. You should find that the angle of incidence is always equal to the angle of reflection

Question 14

How would you investigate the refraction of light?

Answer 14

1. Place a rectangular block of glass on a sheet of paper and draw around it
2. Use a ray box to shine a ray of light into the long side of the block
3. Mark on the paper where the ray of light enters and leaves the block
4. Take the block off the paper and mark the path of the light through the block and the normal at the point where light enters the block
5. Mark the angle of incidence and refraction
6. Repeat this for other angles of incidence and plot your results on a graph