Temperature and Thermometers
Temperature is a measure of how hot or cold something is.
The Instruments designed to measure temperature are called thermometers
Many properties of matter change with temperature. For example, most materials expand when heated.
(a) Mercury or alcohol-in-glass thermometer
(b) bimetallic strip
Temperature Scales
1. Celsius scale
The most common scale today is the Celsius scale, sometimes called the centigrade scale.
On the Celsius scale, the freezing point of water is chosen to be `0°C` and the boiling point `100°C`. The distance between `0°C` to `100°C` is divided into one hundred equal intervals representing each degree between `0°C` to `100°C`.
2. absolute, or Kelvin,scale
The most important scale in scientific work is the absolute, or Kelvin, scale.
(a) Mercury or alcohol-in-glass thermometer
(b) bimetallic strip
Temperature Scales
1. Celsius scale
The most common scale today is the Celsius scale, sometimes called the centigrade scale.
On the Celsius scale, the freezing point of water is chosen to be `0°C` and the boiling point `100°C`. The distance between `0°C` to `100°C` is divided into one hundred equal intervals representing each degree between `0°C` to `100°C`.
2. absolute, or Kelvin,scale
The most important scale in scientific work is the absolute, or Kelvin, scale.
absolute zero `= -273.15°C`
`T(K) = T(°C) + 273.15K`
3. Fahrenheit scale
United States commonly use Fahrenheit scale.
`T(°C) = 5/9(T(°F)-32) or T(°F) = 9/5T(°C)+32`
Thermal Equilibrium:
If two object at different temperatures are placed in thermal contact (meaning thermal energy can transfer from one to the other), the two objects will eventually reach the same temperature