Synthetic Fibres and Plastics — Science STD 8 — Question

Write the use of friction.

Mention the reason that brings the sound of fire crackers to our ears.

Discuss the characteristic properties of plastics.

The moment we put our ear to the railway line, we can hear the sound of an approaching train even when the train is far off but its sound cannot be heard through the air. Why?

Suggest three measures to protect ourselves from lightning.

We have a stringed musical instrument. The string is plucked in the middle first with a force of greater magnitude and then with a force of smaller magnitude. In which case, would the instrument produce a louder sound?

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 is meant by saying that metals are:
Malleable

Explain why, we are advised not to sleep in a room having closed doors and windows, with a coal fire burning inside.