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Q1. In Activity 7.1, four pins I, II, III and IV are stuck with wax on a metal strip, with pin I closest to the candle flame. In which order will the pins fall?
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Q2. In Activity 7.1, the pins fall from the metal strip because
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Q3. Hot tea kept in a clay cup or porcelain cup stays hot for a longer time than tea kept in a metal cup mainly because
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Q4. Woollen clothes keep us warm in winter mainly because
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Q5. On a cold night, two thin blankets used together often keep us warmer than one thick blanket of the same total thickness because
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Q6. Some houses are built with outer walls made of hollow bricks. These walls keep the rooms warm in winter and cool in summer because
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Q7. When the air around a candle flame gets heated, it rises up because, on heating, the air
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Q8. In Activity 7.3, a grain of potassium permanganate is placed at the bottom of a beaker of water and a candle is lit below the centre. The coloured streak is observed to
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Q9. When an agarbatti (incense stick) is burnt, its smoke rises upward in the room because the smoke
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Q10. In Activity 7.4, equal amounts of soil and water are placed in two identical bowls in sunlight, and the temperature of each is measured every five minutes for twenty minutes. The observation is that
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Q11. In the water cycle, water in the oceans, rivers and lakes gets heated by the Sun and turns into water vapour. This process is called
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Q12. When water vapour rises high in the atmosphere, it cools down and changes back into tiny water droplets that form clouds. This process is called
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Q13. In the water cycle, water that falls from the clouds in the form of rain, snow or hail is collectively known as
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Q14. The process by which surface water seeps through soil and rocks to reach beneath the surface of the Earth is called
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Q15. Anjali wonders why people in Jaipur generally prefer light- or white-coloured clothes during summer. The best reason from the chapter is that light-coloured clothes
