physics 1

Conduction:- energy transfer by solids

Convection:- energy transfer by gases and liquids

Radiation:- energy transfer through empty space.

 Conduction Steps:- Particles vibrate when they get heat energy,and heat energy is passed on as particles touch eachother when vibrating.

Convection Steps:- When air is warmed, it gains energy and particles vibrate more. They spread out and warm air is less dense and RISES. Cooler air moves in to take its place.  PARTICLES NEEDED TO FLOW FREELY!!!

Solids:- Density is much HIGHER than gas

• Particles are held next to each other (FIXED POSITIONS)

Liquids- Density is much HIGHER than gas

• Particles have space between-seperated

Gas:- Density is LOW compared to solids and liquids

• Particles are spread out (far apart!)

*Uses Solar energy to heat water!!

Steps:-

• Solar radiation obserbed by Solar panel
• Copper pipes on metal plate that are painted black!

Evaporation:- turns liquid into gas

Can be increased by:- 

• Increasing the surface area
• increasing the temperature

Eg. Cooling by Evaporation

1.particles on top of surface ABSORB energy from remaining particles and temp. of the liquid falls.

Condensation:- turns gas into liquid

Can be increased by:-

• Increasing surface area
• Reducing the remperature of surface

1. when gas LOSES energy and particles come close together again, forming a liquid.

Minimising Heat Loss in Houses!

• Cavity wall insulation:- foam squirted into gaps between bricks reduces radiation and conduction
• Roof insulation:- traps air between fibres -> prevents conduction
• Curtains:- prevents heat loss though convection
• Double glazing:- traps air between window panes/glass -> convection
• Carpets:- prevents heat loss thgough floor..less lost by conduction.