Pollution of Air and Water — Science STD 8 — Question

How does the classification of matter help in understanding chemical reactions?

Why is rainbow usually seen after heavy rainfall?

What do you understand by amplitude of vibration?

A person is in open space during a thunderstorm with no shelter (not even a tree) available nearby. Describe the safe position which he should take to protect himself from lightning. Why is this position considered safe?

Explain the concept of solubility and the various factors that affect it.

It is often read in the newspapers as well as advised by our elders that we should say 'No' to drugs. What are actually these drugs? Mention some of their harmful effects.

What is a crop? Give two examples of crops.

Mention the necessary conditions for a force to come into play.

A father and son pushed their car to the side of road as it had stalled in the middle of the road. They experienced that although they had to push with all their might initially to move the car, the push required to keep the car rolling was smaller, once the car started rolling. Explain.