worksheet-I
Matter in our surroundings		CLASS-IX

.What are the conditions for 'something' to be called matter?  Can matter change its state? State the conditions under which it changes.

. When sugar is dissolved in water , there is no increase in the volume.Which characteristics of matter is illustrated by this observation? .  Why do we see water droplets on the outer surface of a glass containing ice-cold water?

Explain why there is no rise in temperature of water when it starts boiling although it is still being heated.

What is dry ice? Why it is known so?  .Naphthalene balls disappear with time without leaving any solid. Why?  A drop of ink and a drop of honey is placed in water. Which of the two will spread faster-and Why? Ice floats on water. Why?  The boiling point of water is much higher than that of petroleum ether. In which of the two the intermolecular forces are strong?  Explain why a small volume of water in a kettle can fill a kitchen with steam.  Give one example of diffusion of one solid into another solid. Name two gases that which dissolve in water by diffusion .What is the importance of this process in nature? The Kelvin temperature is 270K. What is the corresponding Celsius scale temperature?  Explain two reasons for saying that wood is a solid.