Winds, Storms and Cyclones — Science STD 7 — Question

What are decomposers? Name any two of them. What do they do in the forest?

Measure the breathing rate of the members of your family. Evaluate
(i) If the breathing rate of males is the same or different from that of females.
(ii) If the breathing rate changes with age.

Sorter’s disease is an occupational hazard. Explain.

Write how the following seeds are dispersed?
(I) Seeds with wings
(II) Small and light seeds
(iii) Seeds with spines/hooks

The raw and baked soil differs from each other. How they are different? How can you prepare matkas from soil?

During the summer, you see that fruits ripen faster when left in a paper bag. Using your understanding of scientific reasoning, how can this observation lead to an experiment? What variables would you test to explore this change further?

On last Monday, Pankaj was dealing with immense cough and cold. Besides this, he was suffering from a headache. So, he decided to take a leave on that day so that he could take some rest at his home. After one hour he thought to check his fever through a clinical thermometer, so before using it, he washed it and started shaking it very fastly in his hand, so that the mercury level of thermometer gets reduced. At the same time, his elder brother Vishwas scold him and suggested him to shake the thermometer slowly.
(i) State some precautionary measures while checking the fever through a clinical thermometer.
(ii) Mention the values showed by the elder brother of Pankaj (i.e. Vishwas).

State two experiences that made you think that air exerts pressure (other than those given in the text).

When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place.