Describe a solid specific heat capacity experiment
Plan measurements for an insulated block and evaluate the temperature and energy assumptions.
Extended only (Supplement); Physics 0625, 2026–2028, section 2.2.2. These lessons explain average particle kinetic energy, calculate specific heat capacity and describe solid/liquid methods. Written calculations and method analysis are self-checked
Before you begin
- Use c = ΔE/(mΔθ).
- Distinguish heater input from sample energy and voltage from current.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Where should the voltage measurement be taken for heater input IVt?
What you will learn
- Describe a teacher-supervised solid heat-capacity method and the measurements needed.
- Explain insulation, thermal contact, temperature lag and apparatus energy.
Measure a defined solid sample
In a teacher-supervised method, measure the mass of a suitable solid block. An appropriately rated low-voltage heater and thermometer fit the block's prepared holes with suitable thermal contact. Insulate the block and use the laboratory's approved procedure; this written description is method practice, not evidence that a learner has operated the apparatus safely or competently.
Record initial temperature, elapsed heating time, voltage across the heater and current through it. The ammeter belongs in series with the heater, while the voltmeter reads across it. Use steady readings or a justified mean for the input IVt. Record a representative final block temperature rather than confusing heater temperature with sample temperature.
Check the assumptions before naming c
Use the measured block mass and final minus initial block temperature. If the method initially assumes all heater input warms the block, c = IVt/(mΔθ) is an apparent value. State this assumption. Energy transferred out, heater/probe heating and imperfect temperature uniformity need evaluation rather than disappearing because the apparatus is insulated.
Good contact and appropriate waiting/monitoring under the teacher's method help account for probe response and temperature differences. Repeat suitable runs and compare consistency. Insulation reduces transfer; a larger useful temperature interval may improve relative reading precision, but excessive heating can worsen losses or leave the intended conditions. A repeatable estimate is not automatically unbiased or a practical-assessment pass.
Pause and explain
A lagging probe records a rise smaller than the representative block rise. What happens to IVt/(mΔθ)?
Worked example
A written block trial supplies V = 12 V, I = 2.0 A, t = 300 s, m = 0.80 kg, initial 20°C and final 30°C. Find the all-input apparent c.
Show the worked solution
- IVt = 12 × 2.0 × 300 = 7200 J.
- Δθ = 30 − 20 = 10 K.
- Apparent c = 7200/(0.80 × 10) = 900 J/(kg K).
Answer Apparent c = 900 J/(kg K), assuming all heater input warms the block.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Describe the measurements needed for the low-voltage solid-block method.
Give me a hint
Connect each measurement to the sample calculation.
Compare my reasoning
- Measure block mass and initial/final representative temperatures.
- Measure voltage across the heater, current in series and elapsed time.
- Find input IVt, state energy assumptions and divide the appropriate sample gain by mΔθ.
Mass, temperature interval, heater voltage/current and time, with an explicit energy account.
Look for these in your work
- Identify the correct meter positions.
- State the sample-only assumptions.
Calculate the apparent c for 12 V, 2.0 A, 300 s, mass 0.80 kg and a rise from 20°C to 30°C.
Give me a hint
Use IVt and the temperature difference, then label the estimate.
Compare my reasoning
- Input is 7200 J.
- mΔθ = 0.80 × 10 = 8 kg K.
- 7200/8 = 900 J/(kg K), assuming all input reaches the block.
Apparent c = 900 J/(kg K).
Look for these in your work
- Use the heater's electrical input.
- Keep the assumption visible.
Two insulated block runs give similar apparent c values. A student says this proves zero loss and completes practical assessment. Evaluate both claims.
Give me a hint
Consistency and competence require different evidence.
Compare my reasoning
- Similar results support repeatability of the written measurements.
- Shared losses or probe bias can remain in both runs.
- Written data analysis does not demonstrate supervised apparatus competence or complete a practical-assessment route.
Repeatability is supported; zero loss and practical-assessment completion are not established.
Look for these in your work
- Separate repeatability from accuracy.
- Retain the practical-assessment limitation.
Common mistakes
- Place the ammeter in series and voltmeter across the heater.
- Use block mass and block temperature, not heater readings alone.
- Repeatability does not prove zero losses or practical competence.
What can you explain now?
Does insulating the block prove that all heater energy stays in it?
Compare with the explanation
No.
Transfer can remain, and other apparatus can gain energy; insulation reduces a problem without proving it absent.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Describe a solid method with the required measurements, meter placement, energy corrections and evidence limits.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.