Temperature Flashcards
What is temperature?
The measure of hotness or coldness of an object
What is the SI unit of temperature?
Kelvin (K)
What are thermometric properties?
Physical properties that change measurably and repeatedly with temperature change
Name the thermometric properties.
Length of a liquid column, gas pressure at constant volume, gas volume at constant pressure, colour of crystals, electrical resistance and the emf of a thermocouple
Explain length of a liquid column.
As liquids rise in temperature, they expand
Explain gas pressure at constant volume.
There is a proportional relationship between the amount of pressure applied (to keep the volume constant) and the temperature of gas
Explain gas volume at constant pressure.
When heating the gas, if we allow the plunger to move under normal atmospheric pressure we can read the volume of gas as temperature changes
Explain colour of crystals.
Some crystals change colour depending on temperature
Explain electrical resistance.
Resistance changes measurably with temperature. As a metallic conductor increases in temperature, resistance increases. As a semiconductor increases in temperature, resistance decreases
Explain the emf (electromagnetic force) of a thermocouple.
A thermocouple consists of 2 different metals joined at 2 junctions. One junction is maintained at a fixed temperature (cold junction) lower than what is to be measured and the other junction measures the temperature (hot junction). The amount of emf generated is proportional to the temperature difference between 2 junctions
What are the three types of thermometer?
Standard thermometer, clinical thermometer and infrared thermometer
What are standard thermometers?
Alcohol or Mercury thermometers
What are clinical thermometers?
They have a constriction (bump) to stop the liquid going down to fast
Infrared thermometers measure…
Heat radiation
