Thermophysics Flashcards
What is expansion
When a solid liquid or gas increases in volume when given heat energy.
What is contraction
When a solid liquid or gas decreases in energy because the heat energy is removed
Give examples of expansion and contraction in everyday life
Bridges train tracks and thermometers
What is conduction
When heat energy travels through a solid
Good conductors
Metals
Copper is one of the best conducting metals
Steel is a not very good conducting metal
Bad conductors
Called insulators
Non metals
Air
What is convection
How heat transfers through liquids and gases (fluids)
Got fluids are less dense than cold fluids so hot particles rise and the cools ones fall as shown in a convection current
Infra red radiation
Infra red radiation is absorbed and emitted by all objects.
Increasing the heat energy of an object increases the infra red radiation it emits.
Sun warms the earth by using radiation as do radiators
What is best at emitting and absorbing thermal radiation
Dark dull objects are better at emitting and absorbing radiation than bright shiny objects
Deference between heat and temperature
Heat is a form of energy
Energy is measured in joules (J)
Temperature is a measurement of how hot or cold an object is
Temper afire is measured in degrees Celsius
How is heat energy often lost
Windows
Roof
Gaps around doors and windows
Walls
Floor
By convection and radiation
Ways to reduce heat loss
Double gazing
Proper roof insulation
Draught excluders
Cavity insulation in the walls
Fitting carpets properly
Curtains
How to save energy
Energy efficient lighting
Modern appliances
Switching things off rather than leaving them on standby
In the saving energy in the home experiment we found that
Double glazing or cavity wall insulation reduces heat loss keeping houses warmer
Radiation
When heat is moved from one place to another without using particles this is why radiation can occur in a vacuum
