APSWREI SOCIETY
LESSON PLAN 4
Class:
Subject:
Lesson:
Topic:
Sub-topic:
IX
Physical Science
Measurement
Vernier Calipers1
Description and principle of vernier calipers
Activities indicating behavioral/Learning outcomes
Content
Analysis/Concepts/Subconcepts
Motivation (or) Testing of
Previous knowledge
Date &Time:
Period :
Medium:
By Teacher
By pupils
What do you need to measure a
physical quantity accurately?
An instrument
How can you measure the length
of an object?
By using scale or tape.
What is the smallest
measurement that can be done by
using an ordinary scale?
Milli meter
What is the length of your
sharpner?
It is 2 centi meter 6 millimeter
and a fraction of milli meter.
How can you measure the fraction
of milli meter here?
By using an instrument having
least count smaller than milli
meter.
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How do you measure the
diameter of a sphere?
Such small lengths, including
diameters and thicknesses can be
measured as fractions of milli
meter with the help of
instruments like vernier caliper,
screw guage etc.
Announcement of the Topic :
Aids/Experiments
to be
done/demonstration
etc
-------
Today let us learn the Description and the Principle of Vernier Calipers.
Method
Evaluation
Activities indicating behavioral/Learning outcomes
By Teacher
By pupils
Aids/Experiments
to be
done/demonstration
etc
Method
Content
Analysis/Concepts/Subconcepts
Evaluation
By showing vernier calipersVernier Calipers :
Vernier calipers.
Who invented it?
Paul Vernier.
How many scales does it consist?
Two.
What are they?
Main Scale and Vernier Scale
What does
resemble?
the
main
scale
What are the
two scales of
vernier
calipers?
An ordinary scale in centimeters and
milli meters
What is the length of one main
scale division (S) ?
1 mm
What is the number of vernier scale
divisions ?
10 vernier scale divisions equal to
how many main scale divisions?
So, N Vernier scale divisions equal
to--?
10
What is it called?
Principle of vernier.
What is its equation form?
(N-1) S = N V
10 V.S.D. =?
Hence, 1 V.S.D =?
9 mm
9 mm/10 = 0.9 mm
What is the difference between 1
M.S.D and 1 V.S.D. ?
What is it called?
By simplifying the equation (N – 1) S
= NV, we get,
S – V =?
S – V = 1 mm - 9 mm = 0.1 mm
9 which means 9 mm
(N-1) main scale divisions( M.S.D)
Least count of vernier calipers
NS – S = NV
NS – NV = S
N(S – V) = S
S – V = S/N
Lecture cum demonstration method
Hence,
Least count (L.C) = S/N.
Description of vernier calipers
:Vernier Calipers consists of a
rectangular steel frame with a
linear scale along its longer
arm which is called Main Scale
What is this instrument?
Vernier calipers instrument, object, black board and chalk piece.
Vernier calipers was invented
by Paul Vernier.
A mechanical device which
combines a main scale and a
vernier scale is called vernier
calipers.
Principle of Vernier : (N-1)
main scale divisions (M.S.D) =
N divisions on vernier scale
(V.S.D)
N V.S.D = (N-1) M.S.D
Let 1 M.S.D = S and
1 V.S.D = V
(N-1) S = NV
NS – S = NV
NS – NV = S
N(S – V) = S
S – V = S/N
S – V is the smallest length
that can be measured by using
vernier calipers which is called
as its least count.
What is the
principle of
vernier?
What is the
formula for
the least
and a sliding attachment with
a suitable scale called vernier
scale.
 A button P with a spring
action helps in fixing the
vernier at any desired
position on the main scale.
 J1 and J2 are Called external
jaws. J1 is fixed jaw and J2 is
movable jaw.
 J3 and J4 are Called internal
jaws . J3 is fixed jaw and J4 is
movable jaw.
 S1 is the long thin metal strip
fixed to the vernier scale.
Aids/Experiments
to be
done/demonstration
etc
Activities indicating behavioral/Learning outcomes
By Teacher
By pupils
Hence, what is another formula for
the least count of Vernier Calipers?
What is the use of button P?
What is the use of external jaws?
Least count (L.C) = S/N =
1 M.S.D.
No. of V.S.D
It can be used to fix the vernier at
any desired position on the main
scale.
They can hold any body firmly and
help to measure its length.
What are the two short jaws called?
Internal jaws
What is their use?
What is the use of long strip S1 ?
They are used to measure the inner
diameters of hollow objects like test
tubes.
To measure the depths of hollow
What is the use of the scale present
on the top of the frame V?
bodies like test tubes
This scale helps in measuring the
dimensions of the bodies in inches
Method
Content
Analysis/Concepts/Subconcepts
Evaluation
count of
vernier
calipers?
What is the
use of
external jaws
?
What is the
use of
internal
jaws?
Behavioural changes expected and achieved :
Knowledge
:
Students can acquire the knowledge of the instrument “ vernier calipers”
Understanding
:
Students understand the construction and principle of vernier calipers.
Application
:
Students can apply the knowledge of principle of vernier in understanding the principle of other
similar instruments in daily life.
Skill
:
Student can develop the skill in drawing the diagram of vernier calipers as well as in doing
practicals.
Assignment/ Home work given
:
Draw a neat diagram of vernier calipers and label its parts.
Signature of the teacher
Signature of the Principal