Page 70 - CT&AI_CLasa_7_Part_1

Changes Around

Us: Physical and
5 Chemical

computational thinking quest

Tick ( ) the correct option.
1. Riya kept an iron nail in water for a few days. Based on the observation, which of the
She observed that a reddish-brown layer following best explains why the flame of
formed on its surface. candle B gets extinguished?
Which of the following conclusions is correct? (Abstract Thinking)
(Abstract Thinking) (a) The wax is completely used up.
(a) It is a physical change because
only colour changes. (b) The temperature of the candle
decreases.
(b) It is a chemical change because a
new substance is formed. (c) The supply of oxygen is cut off.
(c) It is a reversible change because (d) The flame is blown out by moving air.
iron can be cleaned.
4. Observe the pattern:
(d) It is a temporary change as it lasts
for only a few days. • Ripening of fruits Desirable
• Cooking of food Desirable
2. Which group contains only chemical changes?
(Abstract Thinking) • Rusting of iron Undesirable
• Food spoilage Undesirable
(a) Melting, boiling, freezing
Which of the following matches the
(b) Rusting, burning, baking undesirable pattern? (Pattern Recognition)

(c) Cutting, folding, stretching (a) Germination of seeds

(d) Dissolving, melting, freezing (b) Drying of clothes
3. Observe the following diagram carefully:
(c) Pollution due to burning fuels

(d) Making compost

5. Observe the pattern:
Change Observation
Cutting apple Shape changes
Boiling water State changes
A B Burning coal X

68 Computational Thinking-7 (Science)