Physics Lesson Plan
Topic: Introduction to Moment
In partial fulfillment of the requirements for
QCP 521 Teaching of Physics II
Done by:
Cao Huijie (S7879403H)
Lecturer:
A/P Yap Kueh Chin
Supervisor:
Date:
A/P Chen Lai Keat
March 8, 2016
1
Lesson Plan
Topic :
Duration:
Target Class :
Turning Effect of Forces (Introduction to Moment)
70 minutes (double period)
Secondary 3 Express.
Instructional Objectives:
1.
2.
3.
4.
Describe the moment of a force in terms of its pivot, force applied and the perpendicular
distance from the pivot to the line of action.
Describe some relevant daily life examples.
Define and calculate moments using formula M  F  D
State and apply principle of moments for a body in equilibrium to solve problems.
Prior Knowledge :
1.
2.
3.
At the end of lesson, students should be able to:
Before the lesson, students shall be able to:
State and apply Newton’s law of motion.
Interpret and construct force diagram.
Construct perpendicular lines from a point to a line.
New Concepts/Terms:
Turning Effect of Forces
is also known as
Moment or Torque
Clockwise
can be
calculated by
Anti-clockwise
M  F  D
0.25 m
[SI units: Nm]
2
Learning Aids & Resources :
Set Induction :
A half-metre rule
IT :
i)
ii)
PowerPoint slides and overhead projector
Video demonstration on seesaw candle
Non-IT
i)
ii)
iii)
Worksheets (Appendices A, B, C)
Whiteboard and markers
Wrenches
Hands-on :
21 sets of the following apparatus:
a half-meter rule, a mass of 50g, a mass of 100g, string and
scissors.
Set Induction :

Ask students to observe and spot the difference in the way you drop the half-meter
rule, as the following diagram depicts. One is to hold the meter rule at two ends and
let go both ends simultaneously to allow free fall. The other is to hold the meter rule
at two ends and release only one end, so the rule swings down towards the other end.
hand
hand
half-metre
rule

Use this activity to introduce pivot and turning effect of forces (moment or torque)

Get a student (probably a big guy) to open the classroom door as he usually does.
Then ask him to open the door by only pushing near the hinge. He will realize it is
extremely difficult to do so. If the class is not convinced, ask a few more students to
try.

Ask the class to identify the pivot in this case and note the turning effect of the push
on the door. Get the class to see the difference is the distance from the pivot.

Introduce the concept of moment or torque.
3
Lesson Development :
1) Everyday applications
The trigger activity uses the simple action of door opening to let students appreciate physics in
our life. And more daily examples (wrench, crane, can opening etc) are introduced later to bring
relevance of moment to the classroom.
2) Student participation
This will be a student-centred lesson whereby the class works in pairs to investigate the principle
of moment. They will be given the necessary apparatus and worksheet (Appendix B) to deduce
the relationship between clockwise moment and anti clockwise moment. Some students will
also present their solutions to some problems on the board. This helps to keep the students on
task and build up their confidence.
3) Experimental activities
The exploration activity on principle of moment provides hands-on experience and promotes
inquiry thinking to enhance students’ learning.
4) Collaborative learning
After each pair has done the investigative activity, they will share their findings with the class
and answer any questions pertaining to their findings.
5) IT – Interactive multimedia
The lesson will use PowerPoint slides as visual aides and show a video demonstration of seesaw
candle to illustrate the principle of moment.
Lesson Closure:
Get the class to reflect on their learning and share with the class.
objectives of the lesson.
Summarize the main
References:


GCE ‘O’ Levels Physics Syllabus (5052)
Video demonstration of seesaw candle
http://teachersportal.nie.edu.sg/kcyap/Physics2002/O%20Level/Turning%20Effect%20of%2
0Forces/Demo%206%20-%20CG%20-%20Candle%20See%20Saw/candleseesaw.mpg
4
Lesson Plan Proper
Microteaching session is highlighted in italics.
Time
Frame
(min)
Teaching/Learning Activities
Materials
Rationale
Half -Meter
Rule
By comparing two different
types of falling, it introduces
pivot and turning effects of
forces to the students.
Key questions
Induction Activity:
5
Ask students to observe and spot the difference in the way
you drop the half-meter rule. One is to hold the meter rule
at two ends and let go both simultaneously to allow free fall.
The other is to hold the meter rule at two ends and release
only one end, so the rule swings down towards the other end.

Get a student (probably a big guy) to open the classroom
door as he usually does. Then ask him to open the door by
only pushing near the hinge. He will realize it is extremely
difficult to do so. Ask class to think of some daily life
examples of moments.
Blackboard and
marker
Show two wrenches, one with long arm, the other with short
arm. Ask students which wrench would they choose to
unscrew a bolt.
Wrenches
This simple everyday example
brings relevance of moments to
our life and get students examine
the rationale behind.



What’s the main
difference in the way I
drop the rule?
How would you
describe the motion of
the rule?
What has changed in
these two different
ways of opening the
door?
Could you identify the
pivot in this case?
Development of Concepts:
Definition and Calculation of Moments
5
1. Introduce the definition of moments (formula and
units), stressing on the meaning of “perpendicular
distance”, and comparing with the definition of work
done. Go back to the examples of two wrenches with
Through comparing to formula
of work done, it promotes lateral
thinking and linkage to prior

Have you seen the
formula somewhere
else? Also involves
5
Time
Frame
(min)
Teaching/Learning Activities
Materials
Rationale
different length and door-opening activity, ask
students to apply the formula to explain that the
moment required to turn an object is fixed, while
distance is longer, force required will be less.
Whiteboard and
markers
knowledge.
Worksheet
appendix A
(OHT)
Make sure students understand
the perpendicular distance is
from pivot to the line of force by
showing the examples.

Is this the correct way
of drawing
perpendicular
distance? (nonexample)

Wrench, Clock
(in classroom)
Let students realize that force
and distance will influence the
outcome of turning effects.
Use clock to illustrate the
direction of moments.
Which direction shall
I apply the force? F1,
F2 or F3?

What happened if I
change the question to
“find the moment
about point B
instead”?

Have you ever noticed
how a crane keeps its
balance?
10
2. Show some daily life examples of moments, get
students to identify the pivot, the force and construct
the perpendicular distance. During the construction,
the line of force can be extended if necessary. Can ask
students to present their answer on the transparency.
5
3. Using wrench example, ask students to choose the
direction to apply force on the wrench. At the same
time introduce clockwise and anticlockwise moments
using the wrench example.
10
4. Let students try some simple questions on calculation
of moments. Ask a few students to present their
answers on the board if time allows. And use the
working examples to investigate moment about
different points, students will realize the importance
of identifying the pivot.
Whiteboard and
markers
Worksheet
appendix C

It’s easier for students to
visualize and understand using
numerical examples.
Principle of Moments
5
1. Recall the concept of clockwise and anticlockwise
moments, show pictures of cranes to let students
ponder how to balance the moments.
PowerPoint
slides
Key questions
Visual aides to show real life
application of moments.
force and distance?
Why do you feel it’s
harder to open the
door if you push near
the hinge?
6
Time
Frame
(min)
15
10
Teaching/Learning Activities
2. Inquiry Activity (Pairwork)
Give clear instructions and expectations before
grouping the students. Ask one student to tie the
string at 25 cm mark to keep the rule balanced. Then
put the 100g at one side of the string and the 50 g on
the other side to keep the rule balanced. The other
student fills the data table in the worksheet to record
down the mass and the corresponding distance. Let
the students share their findings and induce the
principle of moments.
3. Ask the students to draw the force diagram of their
experiment. Highlight the presence of gravitational
force on all objects on earth. If the gravitational force
is passing through the pivot, no moment is resulted
due to zero distance. Relate the previous crane
example and ask students to apply the principle to
explain how the crane keeps its balance. Show the
video of seesaw candle to get students explain the
observation.
4. Show one working example using principle of
moments. Ask students do a few more questions, in
increasing difficulty.
5
Materials
Rationale
PowerPoint
Slides
Half-meter rule,
string, 50g and
100g masses.
The inquiry and induction
approach is taken here to let
students investigate the principle
of moments themselves. This is
to promote a sense of ownership
towards students’ learning.
Key questions

Is there any pattern
you have recognized?

Are these all the
forces present on the
rule?
Why is the candle
seesawing?
Worksheet
appendix B
Worksheet
appendix B
Pointing out students’ common
mistakes helps them to avoid
making the same mistakes.
Video clip
(Seesaw
Candle)
Worksheet
appendix C

Practice to reinforce the concept.
Closure:
1. Let students write down their reflection of the lesson.
Then ask a few students to share what they have learnt
from this lesson.
Encourages reflective learning
and makes learning more
conscious and visible to the
students.

What are the most
important things you
have learnt in this
lesson?
7
Time
Frame
(min)
Teaching/Learning Activities
Materials
Rationale
Key questions
2. Summarize the concepts taught in this lesson: the
definition of moments, its application in our daily life,
the principle of moments.
3. Ask students to finish the questions in the worksheet
as homework. Tell them that you will check their
work in the next lesson.
Microteaching Reflection
Through the process of micoteaching, I have learnt the following points:





Be very thorough and confident about the content I am teaching. I realized that students could ask any questions related or non-related to the topic
you are teaching, thus it’s essential to be very familiar with the content and prepare beyond the requirement of the syllabus. For example, only by
observing my colleague’s microteaching, I realize some of my misconceptions, like speed of wave is only affected by the medium it is traveling, not
by the wave’s frequency or wavelength as the equation may have suggested v  f .
Listening to my colleague’s microteaching, I realize the importance of student-centred teaching. There are various ways to engage the students, like
doing investigative activities, getting feedback from the students, showing video clips or simulations. In comparison, real life demonstration is more
effective to bring the message across than a demonstration video clip.
Lesson plan helps greatly in structuring the lesson and smooth transition of the contents. It makes me conscious to decide the flow of the ideas so
that students can follow the concepts and don’t get lost in the lesson. The lesson plan also helps me to identify the rationales behind each teaching
activities, so that it’s clear to me which skills are not developed in the lesson and helps me to improve my teaching approaches.
In demonstration or illustration of concepts, it’s important to convince the students what you are saying is true, like if you have two magnets, you tell
students one magnet is stronger than the other, to verify this, you show that the stronger magnet can attract a lot more paper clips than the weaker
magnet. This helps students to clear their doubts and believe in what they are seeing.
I also note that if the demonstration produces quite a few results or you have quite a few questions related to the demonstration, it’s beneficial to
record the observations or students’ answers on the whiteboard. This helps students to stay focused and also makes it much easier for you to refer to
while illustrating the concepts.
I find the microteaching very helpful and beneficial, it opens my mind to various ideas of teaching physics topics and brings my attention to some
common pitfalls. Through sharing and observation, we learnt each other’s strength and weakness.
8
Appendix A
Daily Application of Moments
Draw on the following diagram the pivot, the force and the perpendicular distance.
Indicate whether the direction of the moment too, clockwise or anticlockwise.
spoon
lid
effort
Tin can
effort P
9
Appendix B
Investigation on Principle of Moments
Objectives:

To analyze the effects of clockwise and anti clockwise moment

To investigate the conditions to keep an object at equilibrium

To induce the principle of moments
Apparatus:
 A half-metre rule
 A mass of 50g and a mass of 100g
 Some strings
1.
2.
3.
4.
Use the string to suspend the rule, make sure the rule is balanced. At which marking shall you tie the
string?
Place the 50g mass anywhere on one side of the rule, what effect does it have on the rule? What’s the
moment and the direction of the moment? Show your working clearly.
Place the 100g mass on the other side of rule to keep the rule balanced. At which marking shall you
put the 100g for this to work? What’s the moment produced by this 100g mass and the direction of
the moment? Show your working clearly.
Repeat step 2-3 five times and record the data in the following table. g = 10m/s2
Weight of 100g mass __________________ Weight of 50g mass____________________
1
Data set
Distance of
100g mass
from pivot
(cm)
2
Direction
of moment
produced
by 100g
mass about
the pivot
3
4
Moment
produced by
100g mass
about the
pivot (Nm)
Distance of
50g mass
from pivot
5
Direction of
moment
produced by
50g mass
about the
pivot
6
Moment
produced by
50g mass
about the
pivot (Nm)
1
2
3
4
5
10
5.
Did you observe any pattern in the values you obtained from column 3 and 6? How about column 2
and 5?
6.
Based on your investigation, what do you think are the necessary conditions for an object to be
balanced (in equilibrium)?
7.
Draw a force diagram of the experiment while the rule is balanced with 100g and 50g masses on it.
Indicate ALL forces acting on the rule.
11
Appendix C
Exercises on Turning Effect of Force
1. Find the moment of the exerted force about the pivot O for the following situations, show your
working clearly.
5N
0.75 m
5N
O
O
1.5 m
O
1.5 m
1.5 m
5N
2. Find the moment of the exerted force about the pivot O for the following situations:
1.3 m
O
1.5 m
5N
10 N
O
1.5 m
30
Hint: use trigonometry
12
3. A metre rule with uniform weight is balanced at its centre by two weights, X and Y as shown in
the figure below. If the weight of X is 40 N and the weight of Y is 60 N, find the distance of
weight Y from the support.
0.3 m
d
40N
60N
4. A metre rule with uniform weight is balanced by a weight, Z as shown in the figure below. If the
weight of Z is 40 N and the weight of the ruler
0.1 m
40N
W
13
5. A man of mass 72 kg stands on one end of a see-saw. Two children sit on the opposite end as
shown in Figure 6. If the pivot is assumed to be smooth, which of the following gives the correct
combination of the masses of the children that are able to balance the man?
0.50 m
Man
1.00 m
1.50 m
A
B
C
D
B
A
Child A
Child B
40 kg
45 kg
50 kg
54 kg
50 kg
42 kg
40 kg
54 kg
6. A painter of weight 1000N stands 1.0m from the left-hand end of a uniform plank which is 5.0m
long and weighs 800N. The plank is supported by two trestles each 0.5m from the opposite ends.
The diagram below shows the two upward forces P and Q acting on the plank due to the trestles.
0.5m
0.5m
7.
8.
9.
P
Q
(a) Complete the diagram above to show any other forces which are acting on the
plank. Name each of these forces.
(b) What is the magnitude of the total downward force exerted on the trestles?
(c) What is the magnitude of the total upward force exerted by the trestles on the
plank?
(d) By taking moments about the left trestle, calculate the upward force exerted on
the plank by the other trestle.
14