Q. How does the water kept in an earthen pot (matka) become cool during summer?

Q. For any substance, why does the temperature remain constant during the change of state?

Q. What is the physical state of water at:
a. ${250}^{o}C$
b. ${100}^{o}C$

Q. Why does a desert cooler cools better on a hot dry day?

Q. Convert the following temperature to Celsius scale.

Q. Liquids generally have lower density as compared to solids. But you must have observed that ice floats on water. Find out why?

Q. What type of clothes should we wear in summer?

Q. Why does our palm feel cold when we put some acetone or petrol or perfume on it?

Q. Suggest a method to liquefy atmospheric gases.

Q. The mass per unit volume of a substance is called density (density = mass/ volume).Arrange the following in order of increasing density$-$ air, exhaust from chimneys, honey, water, chalk, cotton and iron.

Q. Give reasons for the following observation:
The smell of hot sizzling food several meters away, but to get the smell from cold food you have to go close.

Q. Why are we able to sip hot tea or milk faster from a saucer rather than a cup?

Q.

Give reasons:
(a) A gas fills completely the vessel in which it is kept.
(b) A gas exerts pressure on the walls of the container.
(c) A wooden table should be called a solid.
(d) We can easily move our hand in air but to do the same through a solid block of wood we need a karate expert.

Q. (a) Tabulate the differences in the characteristics of states of matter.

Q. What are the characteristics of the particles of matter?

Q. Which of the following is (are) matter?

Q. Convert the following temperatures to the Celsius scale.

Q. Give a reason for the following observations:

Q. Convert the following temperatures to the Kelvin scale.
$\left(a\right)$ ${25}^{\circ }C$
$\left(b\right)$ ${373}^{\circ }C$

Q. A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?