What do you interpret from the following:
1.We can easily move our hand in air but not through a solid material.
2.An inflated balloon when kept in a refrigerator gets reduced in its size.
3.A wooden table should be called a solid.
(1)
The resistance encountered by our hand when flowing through air (which being less dense) is quite small compared to that in a solid material (density is high). This is why it is easier to move our hand though air.
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(2)
Due to decrease in temperature the separation between the air molecules inside the balloon will decrease ad thus the ballon will contract.
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(3)
A wooden should called a solid simply because it acts like one. It has a fixed shape and volume, its density is quite high and it is hard to change its configuration.