required practical 2: thermal insulators

what is the first step in comparing thermal insulators?

place a small beaker inside a larger beaker and pour 80 cm³ of hot water into the small beaker

how do you measure temperature changes?

place a thermometer through a cardboard lid into the water, record starting temperature, then record temperature every 3 minutes for 15 minutes

how do you test different insulating materials?

fill the gap between the beakers with the material (e.g., bubble wrap, cotton wool, polystyrene balls) using the same mass each time

what are the variables in this experiment?

independent = type of insulating material; dependent = temperature; controls = mass of material, starting temperature, water volume

how are results recorded and used?

record in a table and plot cooling curves; the slowest cooling indicates the most effective insulator

how do you test the effect of material thickness?

wrap 2, 4, then 6 layers of newspaper around a beaker with hot water, recording temperature every 3 minutes for 15 minutes

what are the variables when testing thickness?

independent = number of layers; dependent = temperature; controls = starting temperature and water volume

what trend is expected when increasing layers?

more layers = slower cooling = more effective thermal insulation