Question

give reasons-we can easily move our hand in air but can't do the same easily through solid block of wood

Answer 1

Because in solids intermolecular space is small and intermolecular force between the particles is high so it is strong and hard thanair

Answer 2

It is because block of wood is rigid...particles are tightly packed...Intermoluculer space is absent and it also have fixed volume and fixed shape. On the other hand, The particles of air have very much intermoluculer space....particles are very loosely packed and they have high kinetic energy.