Synthetic Fibres and Plastics — Science STD 8 — Question

Discuss the effects of friction and how it can be both helpful and harmful.

What name is given to the phenomenon in which the earth shakes suddenly for a very short time?

Name of three liquids which when tested in the manner shown in figure below may cause the magnetic needle to deflect.

State the difference between prokaryotes and eukaryotes.

A new material is discovered that bends light more than water but less than glass. What could be its possible applications in optical instruments? Explain your reasoning.

Why are the voices of men, women and children different?

Explain why, snow shoes stop you from sinking into snow.

While returning from the school, Boojho ate chaat from a street hawker. When he reached home, he fell ill and complained of stomach ache. What could be the reason ?

What are fossil fuels? Name three fossil fuels.

Explain why, we cannot see our surroundings clearly when we enter a darkened cinema hall from bright sunshine but our vision improves after some time.