Ranjit

12.1 Rotation of the Earth 1 · Does the Sun really move across the sky or is it the Earth that moves? The Sun only appears to cross the sky. In reality the Earth turns (rotates) from west to east; that rotation makes the Sun seem to rise in the east, move westward, and set. … Read more

11.1 Sources of Light 1 · Does the Moon actually produce its own light? No. The Moon is non-luminous; it merely reflects sunlight. 2 · Which objects give off their own light? Any luminous object: the Sun, stars, lightning, flames, LEDs, fireflies, some deep-sea animals, etc. 11.2 Does Light Travel in a Straight Line? (Activities … Read more

But how does this process (digestion) happen? Food is pushed through a long tube called the alimentary canal. At different spots along that tube special liquids (digestive juices) break big food pieces into tiny ones the body can use. What do you think is the role of saliva in your mouth? Saliva makes food wet … Read more

How was time measured when there were no clocks and watches? People watched events in nature that repeat—sunrise / sunset, phases of the Moon, seasons. To mark smaller parts of a day they made simple devices: Sundial – uses the Sun’s shadow. Water clock – water drips out (or fills a bowl) in fixed time. … Read more

Activity 7.1 – Pins on a heated metal strip Q 1. Why does pin I fall before pin II? Why don’t all pins fall together?Heat travels along the metal from the candle end toward the far end. The wax nearest the flame melts first, so pin I drops first, then pin II, III, IV in … Read more

Activity 6.1 – Looking at changes from Grade 5 to 8 Q 1. What were the most commonly observable changes among students? Height – most children grow taller. Weight / strength – many become heavier and stronger. Appearance – some boys show tiny moustache hair; some girls start to grow breasts; both may get pimples. … Read more

Activity 5.1 – Table of common changes Q (a) Complete Table 5.1 – what do you observe for each change? S. No. Change Simple observation 1 Melting ice cubes Ice becomes liquid water. 2 Chopping vegetables Large pieces become many small pieces. 3 Boiling water Water turns to steam (gas) and bubbles. 4 Making popcorn … Read more

4.1 Properties of Materials Activity 4.1 – Table 4.1: “Are they lustrous? Hard or soft? What happens when hammered?” S. No. Object / material Appearance Hard / soft Effect of hammering 1 Piece of copper Shiny (lustrous) Hard Flattens into a thin sheet 2 Piece of aluminium Shiny (lustrous) Hard Flattens into a thin sheet … Read more