Thermal Insulation Virtual Lab: Materials, Layers and Lids

This thermal insulation virtual lab follows the GCSE physics required practical on insulating materials. A beaker holds 200 g of water at 80 °C. Students wrap it in newspaper, cotton wool, bubble wrap, felt or polystyrene, choose the number of layers and whether to fit a lid, and read the thermometer every 30 s for 20 minutes. They compare the temperature fall in the first 10 minutes and see two things the real practical often hides: thickness matters less and less, and the lid matters most of all. Every number below was read from the simulation.

Curriculum links

• AQA GCSE Physics 8463, required practical 2 (section 4.1.2.1): investigate the effectiveness of different materials as thermal insulators and the factors that may affect their insulating properties.
• Cambridge IGCSE Physics 0625: thermal energy transfer by conduction, convection and radiation, and practical work on cooling.
• Extension for A-level and Terminale: Newton's law of cooling and cooling curves of pure substances.

Simulic is not affiliated with or endorsed by AQA or Cambridge.

Before the lab (5 min)

Ask: "You add more layers of newspaper around the beaker, with the lid on. How does the fall in temperature in the first 10 minutes change?" On a class link this is question 1; the simulation unlocks after students answer.

Method in the simulation

1. On A. Beaker and insulation, set Thermometer to Digital (0.1 °C) and Time speed to ×120. Keep Water at start 80 °C, Room temperature 20 °C and Outer surface As it is.
2. Thickness: set Wrap the beaker in to Newspaper, tick Lid, set Layers to 1 and press Start. When the run has finished, set Layers to 2 and press Start again. Repeat up to 5 layers.
3. Materials: press Clear runs. With Layers 2 and the lid on, run No insulation, Cotton wool, Bubble wrap, Newspaper, Felt and Polystyrene.
4. Copy Fall in 10 min from the Runs table. Switch Graph to compare the cooling curves.

Layers of newspaper (lid on)	1	2	3	4	5
Fall in 10 min (°C)

Material (2 layers, lid on)	None	Cotton wool	Bubble wrap	Newspaper	Felt	Polystyrene
Fall in 10 min (°C)

Expected results

The model has no random error except the thermometer reading, so groups agree to within about 0.2 °C with the digital thermometer.

• Newspaper, lid on: 5.9, 5.1, 4.4, 3.9 and 3.6 °C for 1 to 5 layers. Each extra layer helps, but less each time.
• Materials, 2 layers, lid on: no insulation 7.2 °C, newspaper 5.1, felt 3.0, bubble wrap 2.5, cotton wool 2.3 and polystyrene 1.6 °C.
• The lid: cotton wool ×2 without a lid lost 8.0 °C, more than the bare beaker with a lid (7.3 °C). With no lid, most of the energy leaves through the open water surface by evaporation and convection.
• Glass thermometer: three identical runs with 1 layer gave 5.5, 6.0 and 6.0 °C, because readings are rounded to 0.5 °C.

Questions for students

1. (Prediction, asked again after the lab) How does adding layers of newspaper change the fall in temperature in 10 minutes?
2. Which variables must stay the same when you compare insulating materials?
3. With 1 layer of newspaper and the lid on, what is the fall in temperature in 10 minutes?
4. How much less does the water cool in 10 minutes with 5 layers than with 1 layer?
5. Explain why each extra layer reduces the cooling, and why each layer helps less than the one before.

Answers for teachers: (1) The fall gets smaller, by less with each layer. (2) The starting temperature, the number of layers, the lid and the mass of water. (3) Accept 5.4–6.2 °C (about 5.8). (4) Accept 1.8–2.6 °C (about 2.2). (5) Paper traps layers of air, a poor conductor, so thicker insulation lowers the rate of energy transfer through the sides. Energy still escapes through the lid and the base, so as the side loss shrinks, each layer saves less.

Common misconceptions

• "Insulation stops energy escaping." It only lowers the rate: even polystyrene lost 1.6 °C in 10 minutes.
• "The material itself is what insulates." Most good insulators work by trapping still air.
• "Doubling the layers halves the cooling." Going from 1 to 2 layers saves 0.8 °C; from 4 to 5, only 0.3 °C.
• "The beaker cools at a steady rate." It cools fastest at the start, when it is hottest compared with the room.

Extension

• Cooling curve of stearic acid: open B. Cooling curve of a pure substance with Stearic acid, 10 g, cooled in Air. The temperature stays at 69.3 °C for 16.5 minutes while it freezes, and the sim estimates the latent heat of fusion as 197 kJ/kg. Paraffin wax, a mixture, shows no flat section.
• Newton's law of cooling: switch Graph to ln(T − Tₐ) against time and compare the time constants τ in the Runs table.

FAQ

Can I pin the settings for my class?

Yes. On the Share page, pin Insulating material, Number of layers, Lid on, Starting water temperature and Room temperature in the link's starting values. The thermometer and time speed are not starting values, so step 1 tells students to set them.

Why use the digital thermometer?

The liquid-in-glass thermometer reads to 0.5 °C, which is too coarse for falls of 2–6 °C. Comparing the two is a good discussion about resolution.

Why compare the first 10 minutes?

Every run starts at the same temperature, so the fall in a fixed time is a fair, simple measure of the cooling rate.

Related simulations and guides

Conduction and convection lab – metal rods, layered walls, convection currents Heat Transfer and Insulation – keeping a house warm

For the radiation side of energy transfer, see the infrared radiation virtual lab. For more ideas, see interactive physics lesson ideas.