Temperature Flashcards
1
Q
Heat vs temperature
A
- Heat - a form of energy
- measured in joules - Temperature - measure of the hotness or
coldness of an object
- measured in Celsius/Kelvin
2
Q
why use celsius??
A
- good for every day as it is based on the freezing point of water
- “t”
3
Q
why use Kelvin
A
- no negative numbers so no calculation mistakes
(Lord Kelvin) - “T”
4
Q
absolute zero
A
- the point at which all atomic motion stops
- where Kelvin begins
5
Q
Thermometric Properties
A
- a physical property that changes measurably, repeatedly and predictably with temperature change
- used to measure temperature
6
Q
the length of liquid in a column
A
- thermometric property
- alcohol/mercury expands
- scale measures the length of the column
7
Q
gas pressure
A
- thermometric property
- expands to stay at atmospheric pressure
- plunger in sealed syringe moves
- weights needed to keep volume constant
- pressure applied by weights proportional to temperature
8
Q
gas volume
A
- thermometric property
- will expand to stay at atmospheric pressure with heat
- read volume off syringe
- proportional to temperature
9
Q
colour of crystals
A
- thermometric property
- change colour depending on temperature
- fever strips
10
Q
electrical resistance
A
- thermometric property
- metallic conductor; temp up = resistance up
- semi-conductor; temp up = resistance down
11
Q
emf of a thermocouple
A
- two different metals joined at two junctions (1 kept at a constant cold temperature, the other becomes hot)
- links electromotive force to temperature
- emf generated is proportional to the temperature difference between two junctions
12
Q
uses of thermometric properties
A
- clinical thermometer (alcohol/mercury expands, pushes past constriction, gives time to read temperature)
- IR thermometer (voltage changes between two wires)
13
Q
to calibrate a thermometer
A
- 0 degrees
- 100 degrees
- mark column lengths for both
- plot both points on a graph and draw a line
