# Definition Of Temperature

## Definition Of Temperature

Temperature is the level of internal energy of a system.
(OR) The degree of hotness or coldness of a body is known as temperature.

A reliable measure of the hotness of an object is its temperature.
Temperature is generally measured by using a thermometer.
There are several different scales for measuring temperature.
Americans most commonly use Fahrenheit scale.
In almost complete rest of the world Celsius scale is used for measuring temperature.
Human body temperature is measured by using clinical thermometer.
Normal human body temperature is 98.60 Fahrenheit, equal to 370 centigrade.
Water boils (changes to vapour) at a temperature of 1000Centigrade.
Water freezes (changes to ice) at a temperature of 00Centigrade.
Every substance is composed of molecules (solids, liquids, and gases) as the temperature of the substance increases the molecules in the substance move with more speed.
As the temperature falls, the particles in a material lose their energy and move more and more slowly.
Temperature is not the same as heat.
Example: Spoonful of boiling water and a bucket of boiling water are at same temperature (1000C), but spoonful of boiling water has far less thermal energy than that of bucket full of boiling water.
At -2730C, they can go no slower. This particular temperature is called absolute zero.
In Physics, temperatures are often measured using the Kelvin scale.
Kelvin temperature unit is the same size as the degree celsius.
Kelvin scale uses absolute zero as its zero (0K) (i.e., -2730C = 0K)

#### Worked Example

Ice melts at 00 Centigrade, which Kelvin temperature represents the same?

A. 0 K
B. 100 K
C. 273 K
D. 373 K

#### Solution

Step 1: Kelvin temperature/K = Celsius temperature/0C + 273.
Step 2: Celsius temperature is 00 C.
Step 3: Kelvin temperature/K = 0 + 273 = 273 K
Related terms: Thermometer, Absolute zero, Kelvin, Celsius scale.

Related Terms: Temperature | Specific heat | conduction | convection | radiation