Till now we have learned various types of measurement
such length, weight, capacity and time. But none of these measurements can be
used to find how hot or cold any object is.
When we touch any hot or cold object, we can make out
which is hot and which is cold. But the question here is
how much cold or how much hot. At the same time, it is difficult to know the
exact level of hotness or coldness by touch because the sense of touch varies
from one person to another. To find exact answer, we need some measure of
hotness or coldness.
is the measure of the hotness or coldness of an object with reference to some
standard value. The instrument which measures the temperature of body is known
Each thermometer has a scale. Two different temperature
scales that are commonly used are:
1. The Fahrenheit Scale
The Fahrenheit scale is marked from 32° F to 212° F. 32°
F indicates the freezing point of water and 212° F indicates the boiling point
2. The Celsius Scale
Celsius scale is also called centigrade scale and is
marked from 0° C to 100° C. 0° C indicates the freezing point of water and 100°
C indicates the boiling point of water.
Comparison of two scales
Conversion of Temperature
the temperature is given in degree Celsius:
Step 1: Multiply
the given temperature in degree by 9
Step 2: Divide
the product obtained by 5.
Step 3: Add
32 to the quotient obtained in step 2 to get the temperature in degree
Example: (i) 55° C
Here given temperature is 55°
To convert into degree
Fahrenheit first multiply 55 by 9 and we get product as 495.
Then, divide 495 by 5 and
answer we get is 99.
Now, add 32 to 99 and final
answer we get is 131.
Therefore, 55° C = 131° F
the temperature is given in degree Fahrenheit:
Step 1: Subtract
32 from the given temperature in degree
Step 2: Multiply
the difference obtained from step 1 by 5.
Step 3: Divide
the product obtained from step 2 by 9 to get the temperature in degree Celsius.
Example: (i) 90°
Here given temperature is
To convert into degree
Celsius first we need to subtract 32 from 90 and we get 58.
Then, multiply 58 by 5 we
get answer as 290.
Now divide 290 by 9 and we
get answer as 32.2.
Therefore, 90° F = 32.2° C
C = (F – 32) X 5/9
F = 9/5 X C + 32
A medical thermometer, also known as a clinical
thermometer is a thermometer used to measure body temperature. Most of these
thermometers have both the two scales, Celsius scale and Fahrenheit scale. The
scale runs from 35 degree Celsius to 42 degree Celsius.
The temperature of a healthy human body is
approximately 37 °C or 98.6 °F. The tip of the thermometer is inserted into the
mouth under the tongue or under the armpit for a minute. Then,
the number against the point at which the mercury column stops rising further
indicates the body temperature of the person.