Reducing Unwanted Energy Transfers Flashcards
How does lubrication reduce unwanted energy transfer
Reduces frictional force
When something moved there’s one frictional force acting against it, causes some to be dissipated
Lubricants are used to reduce friction between objects’ surfaces when they move
Example of lubricants
Liquids like oil so they can flow easily between objects and coat them
What is conduction
When an object is heated, work is done to the kinetic energy store of its particles
This causes the particles to vibrate more and collide, work is done between the particles kinetic stored
What it thermal conductivity
Measure of how quickly energy is transferred through a material
What do materials with a high thermal conductivity do
Transfer energy between their particles at a faster rate
What is convection
If the particles are free to move, the particles move faster means that the space between individual particles increase- this causes the density of the region being heated to decrease
What causes the warmer and less dense region to rise above denser and cooler regions
Liquids and gases can flow so energetic particles move away from hotter to cooler regions
How does having thick walls made from a material with a low thermal conductivity reduce energy transfer
The thicker the walls the lower their thermal conductivity, the slower the rate of energy transfer will be
Name 4 types of thermal insulation
Cavity walls
Loft insulation
Double glazed windows
Draught excluders
How do cavity walls reduce the rate of energy transfer
made up of inner and outer wall with an air gap in the middle
The air gap reduces the amount of energy transferred by conduction through the walls
Cavity wall insulation- gap filled with foam can also reduce energy transfer by convection
How does loft insulation reduce energy transfer
Reduce convection currents being created in lofts
How do double glazed windows reduce energy transfer
They have an air gap between two sheets of glass to prevent energy transfer by conduction though the windows
How do draught excluders around doors and windows reduce energy transfer
Reduce energy transfer by convection
