MEASUREMENTS
Vernier
Calipers
The
Functions :
Vernier
caliper is used to measure the diameter of the inside and outside of
an object and measuring the depth with measurement a maximum of 20
cm.
It
consists of a main scale and a vernier scale.
Accuracy
:
Accuracy
of 0.1 mm or 0.01 cm
Parts
of vernier caliper :
Figure
2.1.
A picture of a vernier calipers. The outside jaws are used to measure
the length of a solid or the diameter of sphere. The inside jaws are
used to measure the inner diamater of a tube.
Reading
of scales the vernier calipers :
a. Look
at the numbers on Main Scale (MS) before the zero Nonius
scale (NS)
In
the example problems: SU = 5.8 cm
b. Look
at the numbers on Nonius Scale (NS), which coincide
In the
example problems: SN = 5 x 0,01 cm = 0.05 cm
(ingat
angka yang berhimpit dikalikan dengan accuracy)
c. Actually
value (AV) in the measurement
AV = MS +
NS = 5.8 cm + 0.05 cm = 5.85 cm
(Remember
to add up the units must be the same)
Micrometer
Screw
We
can use a micrometer to measure very small lengths to an accuracy
of 0.01 mm.
It consists of a main scale and a nonius scale like vernier caliper.
Micrometer
is used to measure the diameter of fine wire, the thickness of paper
and other very short lengths with measurement a maximum of 25 mm.
Figure
2.2.
A picture of a micrometer screw gauge. It has two scales: the main
scale on the sleeve and the circular scale on the thimble. Turning
the thimble and moving the circular scale up or down one division,
will cause the spindle to move 0.01 mm or 0.001 cm horizontally.
Reading
of scales the micrometer screw :
- Look at the numbers on the Main Scale (MS) before numbers Nonius scale (before the vertical line)
That
look is the number of 2.5 mm the value of MS = 2.5 mm
- Look at the numbers Nonius scale (NS), which coincide (garis MS dan NS berhimpit). Which coincide is number 20,
NS
= 20 x 0.01 mm = 0.20 mm (remember the figures coincides with the
precision of a micrometer multiplied
= 0.01 mm)
- Actually Value (AV) in the measurement
AV
= MS + NS = 2.5 mm + 0.20 mm
= 2.70 mm
Measurement
of Volume
1.
Regular Volume
The
volume of an object with a regular shape can be calculated after
measuring the lengths of its sides, its diameter, or other lengths.
Then the appropriate formulae (as described below) for the volumes
are used. The SI units for volume is cubic metres (m3).
Volume
of a cube = length3
Volume
of a sphere = 4/3
r3 (where r
is the radius)
Volume
of a cylinder =
r2h
(where r is the radius and h is the height)
Volume
can be expressed as mm3,
cm3
or m3.
Sometimes you will see litres being used.
1
litre (l)
is equivalent to 1000 cm3.
2.
Irregular Volume
The
volume of an object with an irregular shape can be measured by using
a measuring cylinder or displacement can. Two figures below are shown
methods to measure the volume of an irregular shape object.
This Material can be downloaded in here
Individual Task download in here
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Vernier
Caliper
Micrometer
Screw
Graduated Cylinder
Graduated Cylinder
Triple-beam Balance
