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Concept Map
Heat Transfer in Nature
has three processes
Conduction
in solids
Particles don't move · Needs medium · Metals = good conductors
Convection
in fluids
Particles move · Sea/land breeze · Water cycle
Radiation
no medium needed
Sunlight, fireplace · All objects radiate
Sun's radiation powers
Water Cycle
leads to
Infiltration & Groundwater in Aquifers
Mind Map
Heat Transfer in Nature
Chapter 7 · Class 7 Science
7.1
Conduction
Particle-to-particle · No particle movement · Solids · Good conductors (metals) vs poor conductors (wood, air)
7.2
Convection
Particles physically move · Liquids & gases · Hot fluid rises, cool fluid sinks · Convection current
7.2.1
Land & Sea Breeze
Land heats/cools faster than water · Sea breeze (day) · Land breeze (night) · Wind reversal at coast
7.3
Radiation
No medium needed · Travels through vacuum · Sun's heat · Light colours reflect, dark absorb
7.4
Water Cycle
Evaporation → Condensation → Precipitation · Redistribution & replenishment of water · Driven by Sun
7.4.1
Seepage & Groundwater
Infiltration · Clay slowest, gravel fastest · Aquifers · Rainwater harvesting · Ice Stupa (Ladakh)
Key Terms and Definitions
- Conduction
- Transfer of heat from hotter part to cooler part of an object, particle-to-particle, without the particles moving from their positions. Occurs mainly in solids.
- Good Conductor
- A material that allows heat to pass through it easily. All metals are good conductors.
- Poor Conductor (Insulator)
- A material that does not allow heat to pass through easily. Examples: wood, glass, clay, air.
- Convection
- Transfer of heat by the actual movement of particles of liquids or gases from a hotter to a cooler region.
- Sea Breeze
- Movement of cool air from the sea toward the land during the day, caused because land heats up faster than the sea.
- Land Breeze
- Movement of cool air from the land toward the sea at night, caused because land cools faster than the sea.
- Radiation
- Transfer of heat from a hot object to a cooler one without any material medium. Works even through vacuum.
- Water Cycle
- Continuous movement of water — upward as vapour (evaporation, transpiration), downward as precipitation, and through soil as infiltration — redistributing water across the Earth.
- Infiltration
- Process of surface water seeping through soil and rocks into the ground.
- Groundwater
- Water stored in the pore spaces of underground sediments and rocks.
- Aquifer
- Underground layer of sediments and rocks that stores groundwater; source of well and bore-well water.
