Thermal expansion, heat transfer and energy sources
Answers are for parents and teachers.
1
List 3 household items that conduct heat well and 3 that conduct it poorly.
Well: iron spoon, aluminium pan, copper pot. Poorly: wooden spoon, plastic handle, scarf.
2
A rail lengthens 0.3 mm per °C. By how many mm does it lengthen at 30 °C?
9
3
Electricity: 713 units in 2021 and 628 in 2018 (1 unit = 0.1 billion kW·h). What is the difference?
85
4
Why are layers recommended in winter and light-coloured clothes on summer days?
The air between layers keeps heat in; light colours reflect more sunlight.