Nutrition in Animals — Science STD 7 — Question

How would you prevent rusting in iron objects? Discuss with relevant chemical reactions.

If an object travels different distances in equal time intervals, how do we calculate speed?

What is science and how does it help us understand the world around us?

A sewage treatment plant involves a few steps. Aeration tank, grit and sand removal tank, second sedimentation tank, bar screen, first sedimentation tank.
(i)Arrange all the above steps in the correct order in which they occur in the sewage treatment plant.
(ii)Which step gives most of the sludge?

Define ignition temperature.

Paheli observed that most of the fish in the pond of her village were gradually dying. She also observed that the waste of a factory in their village is flowing into the pond which probably caused the fish to die. Explain why the fish were dying?

What is the role of temperature and pressure in influencing weather pattern?

The polar bear are white in colour. Explain why.

Write the reaction that takes place when iron nails are dipped in copper sulphate solution.

Boojho made an electromagnet by winding 50 turns of wire over an Iron screw. Paheli also made an electromagnet by winding 100 turns over a similar Iron screw. Which electromagnet will attract more pins? Give reason.