Resources: Class presentation and handout. Optional: equipment to demonstrate an experimental method for calculations of specific heat capacity. Copper block wrapped with insulation with 2 holes for a thermometer and heater, thermometer, pipette to put water in the thermometer hole, 30 W, 12 V heater and power supply, insulation to wrap around the blocks, ammeter and voltmeter, five 4 mm leads and a stop watch or stop clock.
Handout: Students record method for using an ammeter and a voltmeter to calculate the power and then the energy supplied. A table to record results and process to work out energy transferred. Students then use this to plot a graph and calculate gradient to work out the specific heat capacity.
Ask the students to list 3 examples which show why knowing the specific heat capacity of a material is important.
Use the handout to introduce each aspect of the experiment. The students are to consider the hypothesis and what the question is asking them to do. They should make a prediction of the outcomes and plan in an organised and systematic order. They should consider hazards and make a full risk assessment. Additionally, they should consider the sources of significant error to the validity of the data that they will collect. They should understand how to process that data and make mathematical calculations by rearranging the formula to find for the variables. They should conduct a thorough analysis of the data that they collect.
Career Film: This is Robert Alford. Robert works in the Government Office for National Nuclear Laboratory.
Expert Film #1: This is Dr. Tim Gregory, who works as a Chemical Analyst for National Nuclear Laboratory. Tim talks about specific heat capacity.
Expert Film #2: Specific Heat Capacity of Aluminium Experiment - GCSE Physics Required Practical.
The students should follow the presentation to firstly look at the simplest way to calculate specific heat capacity from experimental data. They should then watch the videos to explore more accurate methods for calculating specific heat capacity. Using the handout, the students should work through the method and calculations needed for the required practical.
Challenge Task: The specific heat capacity of iron is 470 J/kg oC. The specific heat capacity of aluminium is 880 J/kg oC. It takes nearly twice as much energy to increase the temperature of aluminium to iron. Why do you think this is? Use ideas about relative atomic masses and moles of atoms to explain this. What is molar heat capacity? How could this be used?
Look up the theoretical value for the specific heat capacity of copper. How does your answer compare? Is your answer higher or lower? Can you explain why? How could you improve the experiment to reduce the error?