Give reasons:
We can easily move our hands in the air but to do the same through a solid block of wood we need a karate expert.
Answer
The particles of air (gas) have very less force of attraction between them, thus causing large intermolecular spaces
whereas the particles of solids are very tightly packed due to very high force of attraction between its particles.
Due to the difference in the amount of space between the particles , we can easily move our hand in air but to do the same through a solid block of wood we need a karate expert (who uses technique and large force).