Inertia Apparatus

What happens when a tablecloth is whisked from beneath a load of dishes? Now there's a way to demonstrate the scientific principle while keeping your dishes safe. Place the ball on the card and pull back the spring. The card (tablecloth) shoots forward but the ball (dish) drops back to the post (table). Actually, the ball did move but it promptly settled back. Try the same experiment with a coin. Includes glass ball (with flat spot), card, plastic base, post, hardware and instructions.