Physics IA · B · The particulate nature of matter · topic 5 of 30
Specific heat capacity: can you beat the heat loss? · IB Physics IA idea: guide, sample graph and step-by-step plan
compare with the data book, but explain the GAPThe textbook value for a metal is easy to look up. Getting your own measurement close to it is a fight with the room.
- ✓ you like precise measurement
- ✓ you enjoy hunting for what goes wrong
- ✓ you want to compare with a data-book value
The big idea
← heat loss is your RQ hook!Electrical energy E heats a block of mass m, so E = mcΔT and a graph of ΔT against E has gradient 1/(mc). Every joule the block loses to the room makes c look larger than it is. You will compare your result with an accepted value, so the quality of your analysis lies in the heat loss and what you do about it. A strong IA shows the line bending and uses the early, low-loss part, or corrects for it, with reasons.
Make it yours: pick one twist
Copying a classic won't show your choices. Pick one of these (or invent your own) and your IA becomes yours.
Swipe for more twists →
Compare no lagging, one layer and several layers.
→ Heat loss becomes the independent variable; your graph compares how far each run falls below the ideal line.Cool the block after heating and use the cooling curve to estimate the loss.
→ Gives a corrected c with a clear method; needs extra theory and an extra graph.Aluminium and copper blocks of similar mass.
→ A second result to compare with accepted values; the analysis compares gradients and the evaluation asks about differences.Use a low and high heater power for the same energy.
→ Tests how heat loss depends on time and temperature; your graph has two lines to compare.Replace the thermometer with a temperature probe.
→ Many more points and no reading error; the evaluation compares methods.Cooking pans, storage heaters or engine blocks.
→ Gives the introduction a purpose; the physics and graph stay the same.Your Physics IA research question: run the check
Write your own question first. Then make sure it ticks every box:
- Names one independent variable and its range (energy supplied, lagging, or metal) and how many values.
- Names one dependent variable and how it is measured (temperature rise, from which thermometer, at which point).
- Says what stays fixed (mass, heater power, lagging, thermal contact, starting temperature).
- Says what you compare with (an accepted value, and how you will judge agreement).
- Is narrow enough for about 10 hours, with at least 6 energy values and a repeat.
The set-up
One way to arrange it. Draw yours with the real block, lagging, meters and the position of the holes.
How your Physics IA could be laid out
The usual order for a topic like this, what each part needs to show, and roughly how much of your 3,000 words it takes. The words are all yours.
Your question; where specific heat capacity matters (cookware, buildings, engines); what you expect and why.
Specific heat capacity and the equation E = mcΔT; electrical energy supplied; why heat loss matters; the accepted value and where it comes from.
Independent, dependent and controlled variables, each with how you set, measure or hold it, and why it matters.
Mass measured; holes with oil for contact; lagging; how energy is read; how long you wait for the temperature to settle; repeats.
Short and specific: hot block, heater power supply, cooling before handling.
One table: energy, initial and final temperature, units and uncertainties in the headers.
Temperature rise and its uncertainty, c from the gradient, and the percentage difference from the accepted value.
ΔT against E with error bars and fit; what the gradient is; the effect of heat loss on the line.
Answer with numbers: your value, how it compares with the accepted value, and what explains the difference.
Weaknesses ranked by their effect on your result, each linked to a realistic improvement.
Every source for theory and the accepted value.
What your Physics IA graph could look like
ideal line on the graph too ✓Made-up data, to show you the form of a strong graph, not the answer. Yours will look different. example only
- The ideal line is drawn so the heat loss is visible as a gap.
- Error bars on every point. Both axes carry uncertainty, but the temperature one is larger.
- Decide which part of the line to use for the gradient and say why.
- Start the axes at zero so the intercept is visible. Should the line pass through the origin?
- Another graph to consider: temperature against time at fixed power, which shows the cooling and the loss directly.
Which uncertainty matters most?
Rank by the effect on your result, the specific heat capacity. Heat loss can dwarf every instrument, but it is a systematic effect, not a reading error.
Your game plan
the trial run shows how bad the loss isTick steps off as you go. We'll remember on this device.
0 of 11 done
- Read and predictFind the equation E = mcΔT and the accepted value for your metal. Predict the gradient of ΔT against E and how heat loss will change the line.
- Trial run (1 lesson)Heat the block for a few minutes. Does the temperature keep rising after the heater is switched off? Is the thermal contact good? Fix the problems now.
- Decide range, repeats and timingChoose at least 6 energy values, whether to run in one go or restart each time, and how long to wait for the temperature to settle.
- Reduce the heat lossLag every surface, including the top, and note what you did. Decide how you will show the effect of the loss.
- Collect the dataRecord energy and temperature in the table with units and resolution. Record the starting temperature each time.
- ProcessCalculate the temperature rise and its uncertainty. Decide how you find the gradient and what you do with the heat-loss region.
- Graph and fitPlot ΔT against E with error bars and fit. Choose which part of the line to use and justify it.
- Compare with the accepted valueHow far is your c from the accepted one, and is the difference more than your uncertainty? What explains it?
- EvaluateRank the weaknesses by effect on c. Make each improvement specific to a weakness you found.
- Write, then cutWrite in the order of the layout and stay within 3,000 words. Tables, graphs and references do not count.
- Check before your teacher's draftRun through the checklist below, then get your RQ or draft checked. Your teacher reads one draft only.
Physics you'll need
Traps to avoid in this Physics IA
- Ignoring heat loss and then calling the gap "experimental error".
- Poor thermal contact between heater, thermometer and block, with no oil in the holes.
- Reading the temperature before it has stopped rising after heating.
- Using a very different starting temperature for each run.
- Lagging the sides but leaving the top bare.
- Comparing with a data-book value without saying which alloy the block is.
- Forcing the line through the origin without asking whether the data goes there.
More Physics IA ideas like this
- Salt and ice: how fast does a block melt in brine?●○○
- Cooling water: how well does Newton's law fit?●●○
- Insulation: does double the layer halve the loss?●●○
This guide shows how a topic like this is usually approached. It is not an IA. Your question, choices, data, analysis and words must be your own: change something, tell your teacher where the idea came from, and follow your school's rules on outside help.