Specific Heat Capacity GCSE Physics Practical
An investigation to determine the specific heat capacity of one or more materials.
Students must investigate the specific heat capacity of various materials. The practical links work done to an increase in temperature. Students are assessed on their safe use of appropriate equipment. The investigation involves the measuring of mass and temperature change of a block calorimeter which is heated using an immersion heater. Students will also calculate work done by the heater and plot their results on a graph.
Equipment (per participant)
• Safety glasses
• Calorimeter and blocks (in
various materials)
• Insulating jackets for the
calorimeter blocks
• Thermometer
• 3ml pipette
• Immersion heater
• Bench power supply
• Connecting leads
• Ammeter
• Voltmeter
• Electronic balance (2dp)
• Stopwatch
• Heatproof mat
Method
Preparation and Setup
- Weigh the Calorimeter Block
- Use an electronic balance to weigh the calorimeter block in kilograms.
- Record the weight and material type in a table with columns for weight, temperature, and time.
- Insulate the Block
- Place the calorimeter block in an insulating jacket to minimize heat loss.
- Insert the Heater and Thermometer
- Insert the immersion heater into the large hole in the calorimeter block.
- Add one or two drops of water into the small hole to improve thermal contact.
- Insert the thermometer into the small hole.
- Set Up the Circuit
- Connect the immersion heater, ammeter, and power supply in series.
- Connect the voltmeter across the immersion heater.
Conducting the Experiment
- Start Heating
- Set the power supply to 12V and switch it on to power the heater.
- Record the initial readings on the voltmeter and ammeter. These values should remain constant throughout the experiment.
- Record Temperature Changes
- Note the starting temperature on the thermometer.
- Start the stopwatch and record the temperature every 60 seconds for 10 minutes.
- Switch Off and Handle Safely
- After 10 minutes, switch off the power supply.
- Avoid touching or moving the calorimeter block, as it will be hot.
Repeat the Experiment
- Test with Different Materials
- Repeat Steps 1–7 for calorimeter blocks made of different materials.
Calculations and Analysis
- Calculate the Heater’s Power
- Multiply the voltmeter reading by the ammeter reading to calculate the power of the heater in watts.
- Calculate Energy Transfer
- For each recorded temperature, calculate the energy transferred (work done) by the heater using the formula:
Energy Transfer (J) = Power (W) × Time (s) - Add these values to your table.
- Plot the Results
- Plot a graph with Temperature (°C) on the y-axis and Work Done (J) on the x-axis.
- Draw a line of best fit, noting that the initial part of the graph may curve.
- Determine the Gradient
- Calculate the gradient of the straight portion of the line of best fit:
Gradient = Change in Temperature ÷ Change in Work Done - Calculate Specific Heat Capacity
- Use the formula to calculate the specific heat capacity of the block:
Specific Heat Capacity (J/kg/°C) = 1 ÷ Gradient - This represents the energy needed to raise the temperature of the block by 1°C per kilogram of its mass.
- Repeat for Each Material
- Repeat the calculations for each block, comparing the specific heat capacities of the different materials.
Technician tips
- Power to the circuit must be switched off whilst drops of water are added to the thermometer hole.
- Calorimeter blocks could be distributed as a circus.
- Care should be taken that the calorimeter blocks and immersion heaters are cool before students begin dismantling their equipment.
To do this practical you will need
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