Insulation Investigation

Aim: To investigate whether adding more layers of insulation keeps doubling the effect.

Part A — Does insulation make any difference?

1. Set the layers to None, reset the experiment and start the timer. Read the thermometer every 60 s of sim-time up to 300 s, recording the material, layers, time and temperature in the table each time.
2. Reset, wrap the beaker in 1 layer of wool, and repeat, reading at exactly the same times.
3. Compare the two runs in your table. Is the water cooling at the same rate in both, or does the wool change something?

Part B — Does the material matter?

1. Repeat the 1-layer run with foil and then with bubble wrap, reading at the same times as Part A.
2. Which material leaves the water hottest at 300 s? Use your table to rank the three materials from best insulator to worst.

Part C — Does a second layer double the effect?

1. Using wool only, take a reading at exactly 300 s for no insulation, 1 layer and 2 layers (you may already have some of these readings).
2. Away from the screen, fill in the temperature fall column: how many degrees each run lost between the start (80 °C) and 300 s.
3. How many degrees of cooling did the first layer prevent? How many extra degrees did the second layer prevent?
4. Does the second layer save as many degrees as the first did? Use the pattern in your table to predict what a third layer would do.

Part D — Thinking like an experimenter

1. Why must every run start at the same temperature and be read at the same times for your comparisons to be fair? Which of these does the sim control for you?
2. Look at the readings within a single run: does the water lose more degrees in the first 60 s or the last 60 s? Suggest why, thinking about the temperature difference between the water and the room.
3. A vacuum flask keeps drinks hot for hours. Using your table, which material and how many layers would you choose for a home-made flask — and at what point does adding another layer stop being worth the cost and bulk?