WORKSHOP PRESENTATION

Gautam Bhattacharya

Faculty, SCERT (WB)

LESSON PLAN

SUBJECT: SCIENCE

GRADE: SEVEN

TOPIC: NEWTON’S THIRD LAW OF

MOTION

DURATION: APPROXIMATELY

30 MINUTES

TEACHING POINTS

• Concept of force

• Concept of action

• Concept of reaction

• Concept of Action-Reaction pair

• Relation between Action & Reaction

• Mathematical formulation

• Law governing Action & Reaction

LEARNING OBJECTIVES

• List out types of forces seen around in every day life

• Define force, action and reaction

• Identify the pairs of Action-Reaction forces

• Cite real life examples Action and Reaction

• Describe the process involved in a real life situation where Action-Reaction pair is involved

LEARNING OBJECTIVES (…cond)

• Distinguish the forces in terms of Action and Reaction

• Establish the relationship between Action & Reaction

• Enunciate Newton’s Third Law of Motion• Apply the concept of the NTLM in real life

situations.

ICT TOOLS REQUIRED

• World wide web (internet navigation)

• Wikis / Blogs

• Video clips

• You-tubes

• Digital portfolios

Constructivist strategies employed for teaching

• observe surroundings for points of curiosity

• ask questions

• consider possible responses to questions

• note unexpected phenomena

• identify situations where student perceptions vary

• exploration

• engage in focused activity

Constructivist strategies for teaching (…contd.)

• brainstorm possible alternatives

• design a model

• look for information

• evaluate choices

• experiment with materials

• engage in debate

• observe specific phenomena

• analyze data

Constructivist strategies for teaching (…contd.)

• employ problem-solving strategies

• collect and organize data

• select appropriate resources

• discuss solutions with others

• design and conduct experiments

• propose explanation and solutions

• construct and explain a model

• utilize peer evaluation

Observe surroundings for points of curiosity

• View the online video clip from: www.youtube.com/watch?v=mNM5tHou4IQ

• Watch this NASA video segment from: www.nasa.gov/audience/.../The_Law_of_Action_and_Reaction.html

Questions to Students:

• While driving down the road, a fly strikes the windshield of a bus - the fly hit the bus and the bus hits the fly. Which of the two forces is greater: the force on the fly or the force on the bus?

Questions to Students (…contd):

• Many people are familiar with the fact that a rifle recoils when fired. This recoil is the result of action-reaction force pairs. A gunpowder explosion creates hot gases that expand outward allowing the rifle to push forward on the bullet. Consistent with Newton's third law of motion, the bullet pushes backwards upon the rifle. The acceleration of the recoiling rifle is ...

a. greater than the acceleration of the bullet. b. smaller than the acceleration of the bullet. c. the same as of the bullet.

Questions to Students (…contd):

• In the top picture, shown above, a man is pulling a rope that is fixed to a wall. In the bottom picture, the man is pulling upon a rope the other end of which is tied to an elephant. In each case, the force scale reads 500 Newton. The man is pulling ...

a. with more force when the rope is attached to the wall.

b. with more force when the rope is attached to the elephant.

c. the same force in each case.

OBSERVATIONS BY STUDENTS - I

• Force is an external agent which changes or tends to change the state of rest or of uniform motion of a body in a straight line.

• In nature forces occur in pair.• The pairs of forces are formed by Actions and

Reactions.• In nature there are several examples of Actions and

Reactions.

FURTHER EXPLORATION BY STUDENTS

Can we consider any couplet of forces as Action-Reaction pair? Consider the following:

A horse is pulling a carriage on a level ground. The horse knows the third law of motion. The horse will exert a force forward, and the carriage will exert a force equal to the horse's force but in opposite directions. Therefore, the horse can never pull the carriage forward!

Can you explain how is then the carriage pulled forward?

Visit the following site for a possible suggestion:

http://www.grc.nasa.gov/WWW/k-12/WindTunnel/Activities/third_law_motion.html

OBSERVATIONS BY STUDENTS - II

• Not any couplet of forces may be termed as Action-Reaction pair.

• Isolated body is to be considered for identifying the all the forces acting on it.

• Only the unbalanced force causes acceleration in a body.

EXPLORATION BY STUDENTS

• Virtual trip to science gallery to observe Action-Reaction pair and Acceleration under Unbalanced Force from PBL site of Clarkson University: www.clarkson.edu/k12

• See the Video on:

http://www.khanacademy.org/video/newton-s-third-law-of-motion?playlist=Physics

Collection & Organisation of Data

• The students will prepare a write up in www.edublog.org on occurrence of Action-Reaction pair in nature and occurrence of motion under unbalanced force.

Proposing a Relationship

• Action and Reaction are equal in magnitude but opposite in direction.

In other words,

“To every Action there is an equal and opposite Reaction.”

- Statement of Newton’s 3rd Law of Motion

Construct and Explain a Model

• Follow the link below to construct meaning out of the situations described therein:

http://www.khanacademy.org/video/newton-s-third-law-of-motion?playlist=Physics

EVALUATION

• Visit the following site to see Interactive Simulation on 1-D Motion and solve the problems provided therein: http://phet.colorado.edu/en/contributions/view/3423

• Teacher/Peer/Self evaluation of learner through some of the ICT tools that assist in this diagnostic process like:

e- portfolio, digital mapping, assignment etc.

THANK YOU…

…for your kind audience