4. Use the kinetic theory to explain the following

(a) When you take a block of butter out of the fridge, it is quiet hard. After 15 minutes it is soft

enough to spread

Air particles hits the butter particles from collisions that air transfer kinetic energy to the butter. The butter particles then begins to move from each other more faster. So when the particles are becoming lose, the butter (solid) turns to soft butter (slight liquid, slight solid).