Materials : Metals and Non-Metals — Science STD 8 — Question

Name any two devices used in everyday life which work on the existence of atmospheric pressure.

Is it possible to extract petroleum from under the sea?

State two advantages of using chemical fertilisers over manures . What would happen if fertilisers are used in excess ?

Compare the motion of particles in the three states of matter with examples.

What is a clone? Name one famous clone.

Which metal is used to galvanise iron to protect it from rusting?

In leaves name the cell organelle and pigment that is responsible for green colour.

A thunderstorm under certain conditions becomes a cyclone. Factors like wind speed, wind direction, temperature, and humidity contribute to the development of a hurricane. Cyclones also occur frequently in tropical regions.
(a) What is a cyclone?
(b) Can a cyclone occur in Delhi? Give reasons.
(c) Which factors contribute to the development of a cyclone?

Give the name of scientist who actually established the relation between sparks produced by amber and thunderstorms. Explain in brief.

What damage can be done when lightning strikes on the earth?