Winds, Storms and Cyclones — Science STD 7 — Question

Unscramble the underlined word in the following sentences :
(i) The discharge of blood in adolescent girls which generally occurs every 28-30 days is nstmnoiaretu.
(ii) The hoarseness in the voice of adolescent boys is due to enlarged iceov xob.
(iii) Secondary sexual characteristics are natural signs that the body is preparing for adulthood and mark the onset of urtvpeb.
(iv) We should say NO to lahoclo and srugd as they are addictive.

How does heat get transferred in these materials? (cooking utensils made of metals)

What products are formed when and acid reacts with a base in a neutralisation reaction?

Burning of crackers is a chemical change. Justify the given statement.

What happens to the air we breathe in, once it reaches the lungs?

Write the effect of China rose petals on acidic and basic solutions.

A car travels 100 km in the first 2 hours and then covers another 50 km in the next 1 hour. Calculate the average speed of the car’s for the entire journey.

Classify the changes involved in the following processes as physical or chemical changes:
(a) Photosynthesis
(b) Dissolving sugar in water
(c) Burning of coal
(d) Melting of wax
(e) Beating aluminium to make aluminium foil
(f) Digestion of food

Name three natural indicators and how they work.

Cocoon is used to obtain silk thread. How?