Measurement of Time and Motion — Science STD 7 — Question

What are salts? Give examples.

Explain a spherical mirror.

Explain the relationship between sanitation and disease.

Rajasthan is a desert state in India. Once while travelling to Rajasthan by train, Boojho observed several streams and rivulets of rain water during the journey but to his surprise he did not see streams of water in the desert region even during rains. Help Boojho find a suitable explanation for this.

Why does a yellow curry stain on a white shirt turn red when it is washed with soap?

Why did we use metal wire for making the electric circuit? Can we not use some other material for the wires?

Discuss various steps of cleaning waste water in a wastewater treatment plant.

Differentiate between assimilation and egestion.

Silk yarn of different textures can be prepared. Define the statement.

Can you think of a way to reverse the chemical changes that occur during cooking? Explain.