Question

We can easily move our hand in air but to do the same through a solid block of wood, we need a karate expert.​

Answer 1

Explanation:

There will be a weak force of attraction between the particles in air. So we can move our hands on air whereas the particles in solid plank are closely packed and a strong force of attraction exists between them. Hence it needs a huge force to overcome the attraction which a karate expert can do

Answer 2

Air is a mixture of gases and since particles of gas are far apart so same is true for air therefore we can easily move our hand in air. But a solid block of wood is hard and rigid that resists any change in location of its particles hence we need a karate expert in case of a solid block of wood.