LENGTH
The S.I. unit of length is the metre.
The symbol for the metre is m.
We need to measure a wide range of lengths in science.
Measurements of length include measurements of height, depth, width, thickness and circumference. Prefixes are added to the metre to help us quantity the different lengths appropriately.
Tape measure-For lengths that are greater than 1m in length a MEASURING TAPE can be used. Measuring tapes come in different lengths, like 60m long.
Metre rule- for measuring lengths up to one. The metre rule is commonly used in the classroom or laboratory . To measure the length of an object, simply place one end of the object against the zero mark and read off the mark on the rule at the other end of the object.
Metre rule- for measuring lengths up to one. The metre rule is commonly used in the classroom or laboratory . To measure the length of an object, simply place one end of the object against the zero mark and read off the mark on the rule at the other end of the object.
Conversions between various units of length:
1km=1 000m
1m=100cm
1m=1/1000km
1cm=10mm
1cm=1/100m
1mm=1/10cm
PARALLAX ERROR
When your eye is in the wrong position for viewing, you may get what is called a parallax error.
External and Internal caliper- Instead of using a soft measuring tape to measure the external diameter of a round object, we can use external calipers. Internal calipers are used to measure the internal diameters of objects.
VERNIER CALIPERS
Vernier calipers are used to measure short lengths and diameters of objects of up to 10cm. It provides a more accurate measurement than the metre rule. The smallest division on the vernier scale is 0.01 cm, whereas the smallest division on the metre rule is only 0.1cm.
USING THE VERNIER CALIPERS
1. Close the jaws of the vernier calipers. Ensure that the zero marking on the vernier scale is in line with the zero marking on the main scale.
2. Place the object within the jaws of the vernier calipers and clamp it firmly in place.
3. Read the length.
PARTS OF THE VERNIER CALIPER
Tail- Used to measure the depth of an object/hole
Inside jaws- Used to measure the internal diameter of an object
Outside jaws- Used to measure the external diameter or width of an object
Main scale reading-The main scale gives measurements of up to one decimal place.
Vernier scale reading- The vernier scale gives measurements of up to two decimal places.
POSITIVE ZERO ERROR
When the jaws of the vernier calipers are closed and the zero marking on the vernier scale falls on the right of the zero marking on the main scale, we have a positive zero error. To determine the value of the positive zero error, close the jaws and look at the vernier scale to see which mark forms a straight line with a mark on the main scale.
NEGATIVE ZERO ERROR
When the jaws of the vernier calipers are closed and the zero marking on the vernier scale falls on the left of the zero marking on main scale, we would have a negative zero error. Similarly, to determine the value of the negative zero error, close the jaws and look for a mark on the vernier scale that coincides with a mark on the main scale.
CHOOSING INSTRUMENTS
Length to be measured Instrument to use Accuracy of instrument
Between 0 and 10cm Vernier calipers To the nearest 0.01cm
10cm-100cm Metre rule To the nearest mm
5cm and above Measuring tape To the nearest mm(short lengths)
or contractor's To the nearest cm(very long
rule lengths)
There are two rulers. The one on the left is a 99 cm ruler and the one on the right is a 45 cm ruler.
Vernier calipers are used to measure short lengths and diameters of objects of up to 10cm. It provides a more accurate measurement than the metre rule. The smallest division on the vernier scale is 0.01 cm, whereas the smallest division on the metre rule is only 0.1cm.
USING THE VERNIER CALIPERS
1. Close the jaws of the vernier calipers. Ensure that the zero marking on the vernier scale is in line with the zero marking on the main scale.
2. Place the object within the jaws of the vernier calipers and clamp it firmly in place.
3. Read the length.
PARTS OF THE VERNIER CALIPER
Tail- Used to measure the depth of an object/hole
Inside jaws- Used to measure the internal diameter of an object
Outside jaws- Used to measure the external diameter or width of an object
Main scale reading-The main scale gives measurements of up to one decimal place.
Vernier scale reading- The vernier scale gives measurements of up to two decimal places.
POSITIVE ZERO ERROR
When the jaws of the vernier calipers are closed and the zero marking on the vernier scale falls on the right of the zero marking on the main scale, we have a positive zero error. To determine the value of the positive zero error, close the jaws and look at the vernier scale to see which mark forms a straight line with a mark on the main scale.
NEGATIVE ZERO ERROR
When the jaws of the vernier calipers are closed and the zero marking on the vernier scale falls on the left of the zero marking on main scale, we would have a negative zero error. Similarly, to determine the value of the negative zero error, close the jaws and look for a mark on the vernier scale that coincides with a mark on the main scale.
CHOOSING INSTRUMENTS
Length to be measured Instrument to use Accuracy of instrument
Between 0 and 10cm Vernier calipers To the nearest 0.01cm
10cm-100cm Metre rule To the nearest mm
5cm and above Measuring tape To the nearest mm(short lengths)
or contractor's To the nearest cm(very long
rule lengths)
There are two rulers. The one on the left is a 99 cm ruler and the one on the right is a 45 cm ruler.
This is a 150 cm soft measuring tape.
This is a 45 cm ruler.
This is the 100 cm/1m ruler, it is used to measure lengths up to one metre.
This is a set of vernier calipers.
The vernier caliper when it is opened.
These are measuring tapes for carpentry often use as a stiff, curved metallic ribbon.
The opening of the vernier caliper.
WE HOPED YOU HAVE LEARNT SOMETHING FROM THIS POST~! THANK YOU!
WE HOPED YOU HAVE LEARNT SOMETHING FROM THIS POST~! THANK YOU!
No comments:
Post a Comment