Scale Lab investigation / Six-week framework
Why do small things
cool faster?
Research question: How does the size of an object affect how quickly it cools?
Start with the research processWhat this is
This is a student-led investigative framework, not a recipe for one predetermined result. Pupils encounter a phenomenon, develop and improve a method, collect evidence, and decide what question should come next.
Begin with the model
Use the Scaling Laws Explorer before designing the investigation. It helps pupils predict how size changes surface area, volume and surface-area-to-volume ratio.
The research process
From a phenomenon to the next question.
Observe
Why does a mug of tea behave differently from a much larger container of warm water? Why might a small animal lose heat more rapidly than a large one? Return to the Scale Lab Explorer and notice what happens to surface area, volume and their ratio.
Ask
Turn the broad idea into a question you can test. Decide what you will change, what you will measure and what must stay as consistent as possible.
Predict
Write a hypothesis before you collect data. Use the explorer to explain how a change in size could affect surface area, volume and surface-area-to-volume ratio.
Design
Choose safe, available apparatus and agree a fair comparison. Define measurement intervals, repeated trials and how you will record observations.
Pilot
Run a small pilot first. If the temperature change is too small, the run is too short, the containers are not comparable or the room conditions dominate, revise the method. Changing a method after a pilot is good scientific practice.
Investigate
Collect repeated measurements carefully. Record what happened as well as the numbers, including any practical problems or changes.
Analyse
Plot temperature against time. Compare cooling rates, repeated trials, averages where appropriate and anomalies. More confident groups can estimate surface area, volume and SA:V for their chosen objects.
Explain
Ask whether the evidence supports the hypothesis. Connect any pattern back to scale and SA:V, while recognising that material, airflow, geometry, ambient temperature and insulation also matter.
Critique
Evaluate uncertainty, limitations and improvements. Did the investigation really isolate the intended variable? What would make the evidence stronger?
Continue
Use the result to create the next research question: different shapes at similar volume, insulation, airflow, materials or different starting temperatures.
Design safely
Choose a fair, practical comparison.
Possible apparatus includes differently sized containers, warm water, thermometers or temperature probes, measuring cylinders, timers and insulation where appropriate. Use what is available; expensive equipment is not required.
Use warm water rather than dangerously hot water. Follow local school safety procedures, avoid spills, and make sure pupils know how hot the water is before handling containers.
Variables to discuss
- Independent variable: the size or geometry you choose to compare.
- Dependent variable: a defined measure of cooling, such as temperature change over time.
- Control variables: starting temperature, material, liquid volume where relevant, room conditions, timing and insulation.
There is more than one defensible design. The important question is whether the method tests the claim pupils want to make.
Collect evidence
Plan a dataset you can defend.
Use a pilot to settle the observation interval and total duration. Then record repeated trials. Keep the table with the work so another group can understand what was measured.
| Trial | Object or container | Size measure | Start temperature | Time interval | Temperature readings | Observations / conditions |
|---|---|---|---|---|---|---|
| 1 | ||||||
| 2 | ||||||
| 3 | ||||||
| 4 |
Print this page or copy the headings into a lab book or spreadsheet. Nothing is submitted to Just How Big?.
Analyse and explain
Look for a pattern, then test your explanation.
Start with temperature against time. Then compare cooling rate, repeated trials, averages where appropriate and anomalies. Ask whether the graph and the observations tell the same story.
Optional mathematical extension
Estimate surface area, volume and SA:V for comparable shapes. Use those estimates to strengthen an explanation, but do not treat them as the only variables controlling heat transfer.
Teacher-friendly timing
A suggested six-week structure.
- Week 1 — Explore the phenomenon: scaling, observation and first questions.
- Week 2 — Design the investigation: research question, hypothesis, variables and method.
- Week 3 — Pilot and improve: test the method and revise it.
- Week 4 — Collect evidence: carry out the main investigation and gather repeated measurements.
- Week 5 — Analyse with a STEM professional: interrogate data, patterns, anomalies and uncertainty.
- Week 6 — Communicate: produce a scientific poster or presentation and propose a next investigation.
Teachers can adapt the timing, combine stages or extend data collection to fit their timetable.
STEM professional role
Join the research process.
A STEM professional is most useful here as a thoughtful questioner, not simply as a careers speaker.
Visit 1
Help pupils see how research questions, measurement and scale appear in real STEM work.
Between visits
Offer optional lightweight feedback on proposed research questions or methods.
Visit 2
Work with pupils on their collected data, interpretations, limitations and next research question.
For teachers
Practical guidance.
Curriculum connections
KS3 science: energy, heat transfer, working scientifically and ecosystems. Mathematics: ratio, powers, graphs, averages and data representation. Computing: structured data and visualisation.
Differentiation
Support groups with fixed recording intervals and graph templates. Extend confident groups through SA:V estimates, rate comparison and a discussion of model limits.
Access and logistics
Use pair or group roles such as timer, measurer, recorder and checker. Plan accessible equipment positioning and ensure external STEM professionals follow the school’s safeguarding and visitor procedures.
Likely misconceptions
Bigger does not mean every property increases by the same amount. SA:V can help explain a trend, but it does not remove the effects of material, airflow, geometry, ambient temperature or insulation.
Continue
What would you investigate next?
Try different shapes at similar volume, insulation, airflow, materials or different starting temperatures. A good investigation should generate the next question.
Licence: This educational resource is licensed under CC BY-NC-SA 4.0. Created by Just How Big? / Katipo Technologies Ltd.