Physics Unit 1

Seite 1

Unit 1.1 Heat radiation - Radiation, convection or conduction... Bigger the temp difference --> faster energy is transferred... Dark, matt surfaces absorb infrared radiation better than light, shiny surfaces

Conduction - Vibrating particles --> extra kinetic energy to neighbours... Metals have colliding free electrons (good conductors)

Convection - Hotter --> Cooler regions, takes heat energy with them... Water gains energy, expands + less dense, rises above cooler water (displaces), convection current

Condensation - Gas cools --> loses kinetic energy, forces pull together -->liquid... Temp low, Airflow low, Density high

Evaporation - Particles must be fast enough + travelling in the right direction... Temp high, Density low, SA large, Airflow high

Energy efficiency - Draught-Proofing (conv), Loft Insulation (cond + rad), Cavity wall insulation (all), Thick curtains (cond + rad), Hot water tank jacket (cond + rad)

Unit 1.2 (Non) + Renewable - Wind, Waves, Tides, Hydroelectric, Solar, Geothermal, Food, Bio-fuels... Chemical --> Thermal --> Heat water --> Steam --> Kinetic --> Electrical... Unreliable, costly, no pollution, loss of habitat, scenery, limited

Unit 1.3 Wavelengths - Transverse --> Light + EM waves... Longitudinal --> Sound waves + Ultrasound

Ray diagrams - http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/waves/generalwavesrev7.shtml