How does Newton's cradle work and demonstrate the principle of conservation of momentum?

Newton's cradle is a device that consists of a row of suspended metal balls. When one ball is lifted and released, it swings and hits the next ball, transferring its momentum. This causes the last ball to swing out with the same force as the first ball. This demonstrates the principle of conservation of momentum, which states that the total momentum of a closed system remains constant unless acted upon by an external force.