NCERT Solutions for Class 6th Science Chapter 6 .2 How to Group Materials? — Activity 6.4: Let us explore
Book page 1056 Updated on2026-09-19
Q1.
Take each ball and drop it from a fixed height. Note the height to which the ball bounces and record it in Table 6.2. Identify the ball that achieves the highest bounce.
Fig. 6.3, page 105 — Different types of balls used for various purposes; all three are of the same size but made of different materials. Redrawn sketch.
Ball
Bounce (high, medium or low)
Tennis ball
Cricket ball
Hand exercise ball
Any other
Table 6.2, page 105 — Bouncing level of the balls. The second column is printed blank.
Answer
Method: stand each ball beside a wall, mark a fixed height (say 1 m) with chalk, drop the ball from that mark without throwing it down, and have a friend note how high it returns. Repeat three times for each ball and take the best reading. Use the same height and the same floor every time, otherwise the comparison is unfair.
Table 6.2: Bouncing level of the balls
Ball
Bounce (high, medium or low)
Reason — the material
Tennis ball
High
Hollow rubber filled with air — squashes on landing and springs back fully
Cricket ball
Low
Cork wound with thread inside a leather cover — hard, hardly changes shape
Hand exercise ball
Medium
Solid soft rubber — it squashes, but a lot of the energy is used up inside
Any other — rubber ball
High
Solid rubber, very springy
Any other — plastic (hollow) ball
Medium
Thin plastic, light; bounces but not as much as rubber
Any other — clay ball
None (it breaks)
Baked clay is hard but brittle
Ball with the highest bounce: the tennis ball.
Why it happens: all three balls are of the same size, so the only difference is the material. Rubber is elastic — it changes shape when it hits the floor and then pushes itself back, returning almost all the energy. Cork-and-leather and baked clay do not spring back, so the energy is lost and the ball stays down.
Check it yourself: Repeat the same drop on sand or on a mattress. Even the tennis ball hardly bounces, because now the floor soaks up the energy. Bounce depends on both surfaces, not just the ball.