Today we discuss How Length of a regular surface is measured
What is length?
Length is the distance between any two points or places. In fact, it is the width, breadth, height, depth, thickness, radius, circumference etc of any object that we measure is the length.
What is a centimeter?
Centimeter is the unit of the length in C.G.S. System. At O°C the distance between two lines of a
platinum – iridium bar kept at the international bureau of weights and measures at Paris in France is taken as a meter. The one hundredth part of a meter is a centimeter.
Foot is the unit of length in F.P.S. At 32°F the distance between two transverse line on a bronze bar kept at the British Exchequer at London is taken as a yard. One third of a yard is called a foot.
1 mile = 1760 yards, 1 yard = 3 feet, 1 foot = 12 inches
The units of Length
In CGS system: cm
In FPS system: foot
In MKS system: metre
Multiples and submultiples of metre
10 mm = 1 cm
100 cm = 1 metre
1000 metre = 1 km
Precautions while taking measurements
- Placement of the object
Object that is to be measured should be placed on the flat surface.
- Placement of rulers
Ruler should be placed along the length of the object to be measured. The measurement will not be accurate
if the ruler or the metre scale is kept at angularly to the length that is to be measured. The ruler must be kept
as close as possible to the object.
- Ensuring the ‘zero’ mark
You have got to ensure the beginning end of the ruler is placed at the zero mark properly.
- Ensuring the eye position
You have to keep your one eye vertically above the point from where you have to measure keeping another eye
shut while taking the measurement.
- Condition of the ruler
The broken ruler, worn out edges ruler and zero mark clearly not visible ruler must be avoided.
Errors that creep in while taking the measurements
- Errors due to eye estimation
Eye estimation is never always accurate. At a time, one point may seem different in views of different
persons. As such, the accurate one is difficult to recognize.
- Zero error
In a scale (generally wooden) the zero point may be not clearly visible. So measurement should be taken
after making sure the zero mark.
- Error in the graduation of the scale
Often when we measure the length of a long object in a metre scale, the smallest gap is mm is not same
throughout due to the manufacturing defect. So taking the measurement with different scales could
minimize the error.
- PARALLAX ERROR
This is most important error that creeps in while taking the measurements when we do not take the readings
Measurement of area
The amount of surface covered by an object or a place is called its area
Area of regular geometric shapes can be found by simple measurements and by using the following formulae
Area of a Circle = π radius 2
Area of a Triangle = 1/2base x height
Area of a Rectangle = length x breadth
Area of a Square = side 2
Sphere = 4 π radius 2
Circular cylinder = 2 π radius x height
12 inch = 1 foot
3 foot = 1 yard
1760 yard = 1 mile
1 inch = 2.54 cm
1 metre = 1.09363 yards = 39.37 inches
100 metre = 109.36 yards
1 km = 0.621 miles
1 mile = 1.609 km
1 hectare = 100 acre = 10000 sq.m.
1 acre = 4840 sq. yards = 4840 x 9 sq.ft.
If you have enjoyed reading How Length of a regular surface is measured post I would be very grateful if you would help it to spread by sharing on social media like Facebook, Twitter, Google+, by clicking on the share buttons below. If you have any questions or comments, feel free to ask them in the comment section below.
See you in my next blog post.
Also Read on Science Reckoner: