Believe it or not, rubber bands display the law of conservation of momentum very clearly. When a rubber band is pulled back by a person applying a force to it, it doesn't have any momentum because the velocity of the rubber band is zero. So when the rubber band is released, it gains velocity and therefore has momentum. So then how would this action demonstrate conservation of momentum? Well, the rubber band causes the person who released it to experience a recoil force. Since the rubber band is much less massive than a human, the momentum we gain by shooting the rubber band is almost negligible but it still occurs. Therefore when shooting a rubber band, conservation of momentum is demonstrated.