HT Temperature Flashcards
Celsius scale
Unit of temperature is called a degree Based on the boiling and freezing points of water Boiling point=100 Freezing point=0 Anders Celsius
Kelvin scale
The unit of temperature is called a kelvin
Kelvin explains behaviour of gases
Absolute zero is the coldest possible temperature its measured in kelvin
0 kelvin= -273 C
373= 100 C
Lord William Thompson Kelvin
Thermometer
Mechanical or electrical device to measure temperature
Usually contains alcohol
Relies on expansion and contraction of the alcohol
Calibration
The setting or correcting of a measuring device
How do you calibrate a thermometer
Place a thermometer in ice, and check if its accurate
Thermocouple
Wires made up of two different metals that are twisted together
When heat is applied to one end an electric current happens
The amount of current depends on the temperature and type of wires
Measures a wide range of temperature
Used in furnaces, jet engines and hot plates
Bimetallic strip
Mad eof two metals joined together
When the strip is heated one metal expands more than the other making the strip coil more tightly
Movement of the strip can operate a switch taht can control a furnace
Often used in thermostats
Conduction
The tranfer of energy throhgh direct contact between particles
This happens when a SOLID touches a SOLID
Conductors
Materials for easy tranfer of heat
Increase the rate of heat transfer in conduction
Silver, copper, iron, aluminum, metals
Insulators
Materials that dont transfer heat easily
Decreases the rate of heat transfer in conduction and are used to control heat transfer
Air, styrofoam, fybroglass
Convection
The transfer of energy through the movement of heated fluids
Occurs in liquids and gases (fluids, takes the shape of its container)
During convection, fluids travel in a circular motion called a CONVECTION CURRENT
Lava lamp, boiling water, radiator
Convection current
During convection, fluids travel in a circular motion
How does convection current work
Warmer fluids sre less dense than cool fluids (more spaces between the particles) causes the fluid to rise up
Cooler fluids are more dense (less space between particles) this causes tehfluid to sink
Fluids are gases and liquids
How can you control heat transfer from convection
You can use a vacuum
Air is removed in a compartment surrounding the liquid container creating a vacuum
Convection is prevented by stopping the air from circulating
(No interaction of fluid particles)
Radiation
The transfer of energy without any movement of matter (radiant energy)
No particles involved
Travels at extremely high speeds (300 000 km/s)
Travels in waves and straight lines
