NCERT Summary - Measurement
Category : 6th Class
Measurement
- Measurement is one of the most useful processes in science and in our daily life. Without actual measurements, we cannot make correct judgments about a given object. It is not always easy to find out the length, area, volume or mass of different objects just by looking at them.
- For the sake of uniformity, scientists all over the world have accepted certain standard units for measuring different quantities. For example
| Quantity |
Standard Unit |
| Length |
Meter |
| Mass |
Kilogram |
| Time |
Second |
- Standard unit of length : Metre
- Meaning of length : Metre can be used as a unit to measure the length of a room, the height of a tree or a building or length and breadth of a playground.
- Short form of standard unit : m
- Other standard units : 10 millimeters (mm) = 1 centimeter (cm)
: 100 cm = 1 meter (m)
: 1000 m = 1 Kilometer (Km)
- Standard unit of area : \[Metr{{e}^{2}}\]
- Meaning of area : Area is the measure of surface of an object
- Short form of standard unit : \[{{m}^{2}}\]
- Another unit of standard unit : \[1\,acre=100\,{{m}^{2}}\]
: \[1\,hectare=100\,acre=1000\,{{m}^{2}}\]
- Standard unit of volume : \[\begin{array}{*{35}{l}}
- Metr{{e}^{3}} \\
- \end{array}\]or cubic meter
- Meaning of volume : The space occupied by an object is called its volume. The space availablein a container is called its capacity. In fact, the capacity of a container is its inner volume.
- Short form of standard unit : \[{{m}^{3}}\]
- Other standard units : When the object is small, instead of considering \[{{m}^{3}}\] as a unit, we may consider \[c{{m}^{3}}\] or \[d{{m}^{3}}\]as a unit. These are read as cubic centimetre and cubic decimetre, respectively.
- The volume of liquids like milk, kerosene and petrol is measured in litres or millilitres \[(ml)\]
1 litre (1) = 0.001 cubic meter
1000 ml = 1 litre (1)
1 ml = 1 \[c{{m}^{3}}\]
- Standard unit of mass : Kilogram
- Meaning of mass : The mass is the measure of the quantity of matter in an object.
- Short form of standard unit : kg
Other standard units (small mass) : Gram and milligram
| 100 gram (g) |
= |
0.1 kilogram |
| 1000 milligram (mg) |
= |
1 gram |
| (large quantities) \[-\] 100 kg |
= |
100000 grams/ 1 quintal |
| 10 quintals |
= |
1 tonnes |
- Temperature is measured in degree Celsius. It is written as\[{}^\circ \]. A thermometer has two standard markings. To make the standard marking on a thermometer, two fixed points are required.
(i) Lower fixed point: It is the temperature of melting ice.
(ii) Upper fixed point: It is the temperature of steam of boiling water.
- The clinical thermometer used by doctors does not have the markings from \[0{}^\circ C\] to \[100{}^\circ C.\] It cannot, therefore, be used to measure the temperature of ice or boiling water. It can measure only a short range of temperatures from about \[35{}^\circ C\] to \[42{}^\circ C.\] It is graduated likewise because the temperature of the human body does not vary beyond these temperatures. The temperature of a normal human body is \[37{}^\circ C.\]
- The standard unit of time all over the world is second. Time for longer events is expressed in larger units. The larger units of time are minute, hour and day.
| 60 seconds (s) |
= |
1 minutes (min) |
| 60 minutes (min) |
= |
1 hour (h) |
| 24 hours |
= |
1 day |
- Months and years are also units of time to express longer time intervals.
