Water: A Precious Resource — Science STD 7 — Question

Out of the two given clocks, a pendulum clock or a quartz clock. Mention which of the clock between the given ones requires an electric cell for its working?

Why caterpillars should not be collected with bare hands?

Stainless steel pans are usually provided with copper bottoms. The reason for this could be that:

Which type of spherical mirror is used as reflectors at sharp turns or blind corners in big shopping malls or as rear-view mirrors in cars?

How was time measured when there were no clocks and watches?

Briefly mention whether mirror change the direction of light.

We should not touch the lighted bulb. Explain, why.

Define wool.

What are quartz clocks?

Name the organ in elephant used for picking up food.