Students’ Learning Outcomes
· Demonstrate how force can change the position and the shape of an object.
· Explore that greater the force, greater the change in the distance covered by the object.
· Design experiments to demonstrate that some objects can return to their original shape after the release of force. Information for Teachers
· When a push or pull is applied to an object, it changes its position or it changes its shape.
· The greater the force, greater the change in the distance covered by the object.
· Some objects return to their original shape after the release of force and some don’t.
Material / Resources
Ball, coins, rubber bands, kitchen sponge, balloon, clay, textbook
Worm up activity
· Place a ball on the floor.
· Ask the students how can they move this ball?
· Ask a student to move the ball.
· Then ask another student to push it harder.
· What happens when you apply more force on the ball?
(Conclude that greater the force, greater the distance covered by the object)
· Give a rubber band to a student ask him/her to stretch it softly. Then ask: Does the shape of rubber band change when stretched?
(Students’ response: force changes its shape)
Development
Activity
· Place a coin on the table.
· Ask students to observe the position of the coin.
· Ask one student to push the coin gently. Note the new position as well as the distance covered by the coin.
· Ask the same student to push the coin with more force.
· What difference do you observe in the two cases?
(Students’ response: Greater the force, greater the change in the distance covered by the object)
· Have other two students try the same activity with a sharpener and eraser and observe the difference in distance covered.
Activity 2
· Give a kitchen sponge to a student and ask him/her to squeeze it.
· Ask the students: What happens when you squeeze it? (It changes its shape by applying force)
· What happens when you release it? ( It regains its original shape)
· What does it show?
(After students response tell them that some objects regain their shapes on removal of force)
· Ask different students to repeat the experiment with a spring.
Activity 3
· Take an inflated balloon.
· Ask a student to press the balloon gently by hands.
· Ask students: What happens when he/she presses the balloon? (It changes its shape)
· Ask what happens when he/she releases it? (It regain its shape after the removal of force)
· Repeat the activity with different students.
Activity 4
· Ask a student to a ball of clay and press it with hands inside a mold.
· Ask the students what happens when you press the clay ball with their hands. (Response: its shape changes)
· Ask that does it return to its original shape when hands are removed. (Response: No.)
· Tell students that some object do not regain their original shape after the removal of the applied force.
Sum up /Conclusion
· Ask the students: What effects of force did you observe today? Write the correct response on the board:
v Force can change the position of an object.
v The greater the force, the greater the distance covered by an object.
v Force can change the shape of an object.
v Some object return to their original shape after the release of force and some not.
Assessment
· Ask the following questions from different students and write the correct answers on the board:
v Which of the things could you change the shape of by applying force.
a) A plastic ball
b) A metal toy
c) A glass cup
v What happens when you stretch the plastic bottle by your hand and release
a) It changes shape
b) It breaks
c) It regain its shape
v When you apply greater force on the bicycle pedals
a) It covers greater distance
b) It slow down
c) It stops
v How could you stop a toy car moving down a slope?
a) Give it a push
b) Put hands in its path
c) It is impossible to stop
v When a force is applied on a rubber band
a) Its shape changes
b) It stays the same
c) It breaks
Follow up
· Survey the classroom to find things that need either a push or a pull to make them move in different directions.· Discuss where pushes and pulls changes the shape of different objects in everyday life and enlist them.
· Find two materials in which objects regain their original shape after the removal of applied force.
· Find two materials in which objects change their shape on applying force but don’t regain their original shape on removal of applied force. Draw their pictures:
