Practicals

Question 1

Specific heat capacity

Answer 1

1. Set up your equipment, ensuring to wrap insulation around the base and sides of the block. The heater should fit snugly into one hole in the block.
2. If the thermometer has an air gap surrounding it when placed in the second hole, drop water into the hole using a pipette to increase thermal contact.
3. If the power of the heater is unknown, switch on the power supply and measure the current and potential.
   Calculate the power using the equation P= IV
4. where I is the current (measured in Amps) and V is the potential difference (measured in volts).
   Keep the power supply on and start the timer. Measure the temperature of the block every 10 minutes.
   Plot a graph of temperature against work done by the heater. Calculate the gradient of the line.
5. Specific heat capacity is the gradient divided by the mass of the block. Since the mass is 1kg, the inverse of
   the gradient = specific heat capacity of the block.

Question 2

Thermal insulation (testing differnt types of materials

Answer 2

Set up your equipment, wrapping four of the five beakers with a different insulating material (using the rubber bands to secure the insulation, ensuring as small an air gap between the beaker and insulation as possible).
2. The beaker with no insulation wrapped around it is the control beaker.
3. Cut circles of cardboard (larger than the mouth of the beaker) to form lids for each beaker.
4. Fill each beaker with warm water from the kettle and record the initial temperature of each.
5. Start the stopwatch and measure the temperature of the beakers every 3 minutes.
Calculate the change in temperature for each beaker (initial temperature - final temperature)

Question 3

Thermal insulation testing different thickenes on insulators

Answer 3

1. Wrap five beakers in varying thicknesses of one insulating material e.g. wrap each beaker in newspaper using one more sheet per beaker.
2. Fill each beaker with warm water, record the initial temperature, and cover each beaker with paper
3. Repeat the experiment as before, measuring the temperature every 3 minutes.
4. Record your results and calculate the change in temperature for each beaker (initial temperature-final temp

Question 4

Resistance

Answer 4

Set up a simple circuit and attach a length of wire along a metre ruler using pieces of tape. Attach a crocodile
clip to one end (x = 0cm on the ruler).
2. Attach the second crocodile clip at x = 10cm on the ruler and record both the current and voltage thro
the wire
3. Repeat by moving the crocodile clip 10cm along the wire and each time recording the current and voltage 92
5. Calculate the resistance of the wire at each point using the equation V=IR, where V is the potential difference measured in volts) and I is the current measured in Amps).
6. Plot a graph of the length of the wire (x-axis, units = metres) against the resistance of the wire at that pr
(y-axis, units = Q)

Question 5

Iv charectorisitc

Answer 5

1. Construct the circuit shown in the diagram
2. Set the variable power supply or variable resistor to the lowest setting for potential difference.
3. Record the current and voltage over the resistor.
4. Increase the current from the power supply by 2V and repeat your readings.
5. Change the resistor to a filament lamp and repeat the experiment.
6. Change the filament to a diode and protective resistor (to restrict high currents flowing through the diode), ensuring the diode is in the correct direction to allow the flow of current through. Change the ammeter to a milliammeter, since the current measured will be smaller than for the other components.
7. Plot a graph of current against potential difference for each component.

Question 6

Density regular shaped objects

Answer 6

Measure the length, height, and width of the object, recording your values to the nearest millimetre.
2. Calculate the volume by multiplying the length, height, and width, giving your value in cm 3.
3. Measure the mass of the object, using the mass balance. Remember to reset the balance with nothing on the scales to reduce zero errors.
4. To calculate the density, use the equation:
5. P= m/V, where p is the density, measured in kg/m 3

Question 7

Density irregular shaped objects

Answer 7

Fill the displacement can with room temperature water and align a measu beaker with the spout. Make sure that the level of water lies below the leve spout, but that there isn’t too much of a gap between the two levels.
2. Place the irregularly shaped object slowly into the can, ensuring not to drop it from a height or cause it to splash.
3. Collect the displaced water and measure the volume of water displaced.
4. The volume of water displaced will equal the volume of the object that cause. displacement.
5. Measure the mass of the object using a mass-balance.