Is Matter Around Us Pure ? — Science STD 9 — Question

Out of solids, liquids and gases:
In which medium sound travels slowest?

What is aquaculture?

During the downpour in a village, the rain water carried away excess of nitrogenous and other compounds present in the soil to a pond. How will they affect the growth of algae and phytoplankton in the pond?

Name one common substance which can be easily changed from one state to another by heating or cooling.

Give an example each for the mixture having the following characteristics. Suggest a suitable method to separate the components of these mixtures:
A volatile and a non-volatile component.

Name the temperature at which:
A solid changes into a liquid.

A person is carrying a heavy weight. He got tired and removed the weight to relax his muscles. Which tissues are involved in this case?

How is matter classified on the basis of physical state?

How much work is done by the gravitational force of earth acting on a satellite moving around it in a circular path? Give reason for your answer.