Heat Transfer Flashcards
How might heat/thermal energy be transferred
Via conduction, convection or radiation
What is the light spectrum?
Red Orange Yellow Green Blue Indigo Violet
What are the three rules of light?
It travels in straight lines
It can be reflected or refracted
It can be absorbed
How fast does light travel
3x10to the power of 8 m/s
300000000m/s
What happens during conduction
Heat energy is transferred into kinetic energy thus causing particles to collide increasing the kinetic energy thus increasing the temperature
What is thermal/infra-red radiation
Everything in the universe emits infra-red radiation which is part of the electromagnetic spectrum
How does the suns heat get to earth through a vacuum
Through thermal/infrared radiation as it is the only heat transfer that doesn’t need particles
What happens to an object while conduction is taking place
The object expands due to the collisions of particles moving about pushing each other further out
What is an advantage of thermal expansion
A bimetallic strip used for thermostats
What is a disadvantage of thermal expansion
Train tracks in the summer change shape
What is conduction
The particles closer to the heat source vibrate faster adding kinetic energy colliding with the neighbouring particles with a greater force. Passing the kinetic energy on, this increases the kinetic energy which increases the temperature.
What is convection
When fluids are heated they expand as explained earlier this makes the fluid less dense meaning the hot fluid rises as it is less dense than the cold fluid
Examples of when convection was used to help something
It was used in the mines to give the miners fresh clean air
The best conditions for radiation
Dark, matte solids are the best emitters and absorbers whereas shiny white solids are the worst emitters and absorbers of radiation
What materials conduct
All solids conduct but metals are the best
