Chapter 7: Heat Transfer in Nature
Why does a steel ladle get hot, smoke rise, a breeze blow from the sea, and the Sun warm us across empty space? In this chapter we explore conduction, convection and radiation, see how they shape clothes, houses and coastal winds, follow the water cycle the Sun drives, and find out how water seeps underground to become groundwater.
In this chapter you will
- explain conduction, convection and radiation
- sort materials as good or poor conductors of heat
- explain land and sea breezes
- describe the water cycle, infiltration and groundwater
Topics
- Conduction of Heat NCERT 7.1
Conduction: heat passes from particle to particle in a solid, from hot to cold, without the particles moving away.
- Convection and Breezes NCERT 7.2
Convection: heat moves by the actual movement of particles in liquids and gases; warm fluid rises, cool fluid sinks.
- Radiation NCERT 7.3
Radiation carries heat with no medium; the Sun's heat reaches us this way.
- The Water Cycle and Groundwater NCERT 7.4
The Sun drives the water cycle: evaporation and transpiration, condensation, precipitation, and return.
Key words
- Conduction
- heat passing particle to particle in a solid
- Convection
- heat carried by moving particles of a liquid or gas
- Radiation
- heat travelling with no medium
- Insulator
- a poor conductor of heat
- Sea breeze / land breeze
- cool air from sea to land by day; from land to sea by night
- Infiltration
- water seeping into the ground
- Aquifer
- underground layer that stores water
Summary
- Heat moves by conduction (solids), convection (liquids and gases) and radiation (no medium).
- Metals conduct heat well; trapped air, wool, wood and clay insulate.
- Land heats and cools faster than water, causing sea and land breezes.
- The Sun drives the water cycle; infiltration fills aquifers, which we must recharge.