An elastic collision is a type of collision in which both momentum and kinetic energy are conserved. This means that the total momentum of the system before the collision is equal to the total momentum after the collision, and the total kinetic energy of the system remains constant.

To better understand elastic collisions, let's consider the example of two billiard balls on a billiards table. When one ball hits another ball head-on, it transfers some of its momentum to the stationary ball. However, the total momentum of the system remains unchanged.

In elastic collisions, the objects involved bounce off each other without experiencing any deformation or loss of energy. This can be seen in situations like a rubber ball bouncing off a wall or the collisions of atoms in a gas.