9.3 heat fat like ur mooo Flashcards
State how solid expands when heated
Particles in solid vibrate at fixed position
Heated: Vibrate faster -> further apart from one another -> solid volume increase
State how solid contract
Cooled: Particles vibrate slower -> move closer to on another -> solid volume decrease
State how gas & liquid expands
Particles move freely
Heated -> move faster & randomly -> distance between particles increase -> volume increase
State how liquid and gas contract
Cooled: Move slower & closer to one another -> volume decrease
What is the use of E & C in thermometer
Mercury is a heat conductor -> E & C
Why is there gaps in railway tracks
Enable them to expand in hot weather
Without gap -> track buckle & overlap -> derail
State E & C in steel bridges
Build w/ rollers and gap on one end
Hot weather -> can expand
State the function of bimetallic strip
Used in device that depend on temperature regulation
State how bimetallic strip works
Made of two different types of metal strips: E & C at different rates
State example of bimetallic function in fire alarm system
Exposed to heat from fire -> copper strip expand faster than steel strip -> bend towards contact point -> completes system & alarm ring
State the rate of E & C of different metals
Aluminum
Bronze
Copper
Iron
How to open tight lid
Submerge bottle in hot water -> expand & open
How to undent a tennis ball
Put in hot water -> air in ball expands
Why electric transmission cables on poles are hung loosely
Prevent from snapping at night -> contract
Why are fuel tanks painted bright colours
Bright colours do not absorb a lot of heat -> evaporation of fuel reduced
Ability to absorb / radiate heat depends on
Type -> shiny / dull
Colour -> Bright / Dark
State the relation between type and colour of surface with absorption and radiation of heat
Dark & dull -> better heat A & R
White & Shiny -> weaker
What is Green Building Concept
Reduce effect of rapid development on the environment & health
What are the features of green buildings
High energy efficiency -> solar energy / renewable energy
Good water flow system, air circulation & lighting
Recycled materials
What is the fastest heat transfer method
Radiation -> does not use any medium to propogate
Is air a good insulator or conductor
Insulator
What happens if insecticide can is thrown into rubbish dump
High heat (weather / burning) increase pressure of can -> explode
