Pupil sheet · Conduction and convection
Conduction and convection — return questions
Name ______________________ Date ____________
Use one to two weeks after the lessons. Keep the notes and the lesson closed.
1. explain / describe / state
A climber's sleeping bag is filled with fluffy fibres and has a metal zip. (a) Supplement. Explain, in terms of particles, why the air trapped between the fibres keeps the climber warm. (b) Describe an experiment, with two cans of hot water and a thermometer, to find out whether the sleeping-bag filling or a cotton sheet is the better thermal insulator. State what you measure, and how the result shows the better insulator. (c) Supplement. A pupil writes: “Energy travels along the metal zip because its atoms move from the warm end to the cold end.” Explain why this is incorrect. (d) Supplement. In the morning the climber holds three mugs of the same hot soup: a steel mug, a pottery mug and a plastic foam cup. State which feels hottest and which feels coolest to hold, and explain why.
(a) Supplement: the trapped air
(b) The two cans
(c) Supplement: the zip
(d) Supplement: three mugs
2. state / explain / describe
A family packs a cool box with food and one frozen ice pack. (a) State whether the ice pack should go on top of the food or under it. (b) Explain your answer in terms of density. (c) Describe how you could show a convection current in air, using a box with two chimneys, a candle and smouldering paper. (d) A pupil says: “The plastic wall of the cool box lets energy in by convection.” Explain why this is incorrect.
(a) Where the ice pack goes
(b) Explanation
(c) The smoke box
(d) The plastic wall