Booklet 4 -heat Transfer Flashcards
Heat is a
Form of energy measured in joules using a joulemeter, temperature.
How hot an object is measured in degrees Celsius using a thermometer
Thermal energy always travels from
Hot to cold
Heat is lost through
Evaporation (sweat)
Dry heat loss (radiation,conduction,convection)
Metabolic rate -body working
Heat travels through solids by
Conduction
Bad conductors are
Good insulators
Heat transfer by a solid bar (atoms)
As heat energy enters the bar it causes the atoms and electrons in the bar to vibrate more. The atom collides with the next and causes it to vibrate and ect, this transfers the heat down the bar. This is knows as conduction.
Why does paper over the wood burns but not the paper over the copper?
The copper asorbs and transfers the heat away from the paper quickly enough to prevent burning. the wood can’t because it’s a poor conductor of heat
Why do objects feel hot or cold?
Heat flows from the object to your hand it feels warm to touch.
When heat flows from your hand to the object it feels cool.
Therefore objects at the same temperature can feel hot or cold
What metal is the best conductor in order
Copper
Aluminium
Brass
Iron
Raidiator example of convection
When air near a radiator is heated it will expand and become less dense. It then rises, allowing cooler air to take its place. This is known as a convection current.
How do gliders stay in the air
They use currents of rising warm air (from earth) to circle upwards and glide between thermals
Heat travels through empty space by
Radiation
Heat transfer by radiation does not involve
Particles
Colour …..?… raidiation
Colour affects radiation emition or abosrption
The colour white doesn’t……
Collect and contain a lot of heat / white reflects not collects
