Activity Based Science Learning >Balancing the Nails

Introduction : We all are very familiar with iron nails. However, in this experiment we shall use them not to strike them inside the walls but to surprise the audience. Let us see how on a single nail an entire set of nails can be balanced. 

Required material : 15 equal-sized nails, each about 2-3 inches long. 

Procedure :

1.         Fix a nail on a piece of wood or some lid so that it remains vertical with its flat top up. We will call this arrangement stand.

2.         Now, ask your friends to balance the remaining 15 nails on the nail fixed to the stand. Your friends will be a real fix attempting to put so many nails in a very small space. But, you come to their rescue by demonstrating how this can be done.

3.         Place a nail on a table so that its head it towards you. We may call it base nail.

4.         Now, arrange the remaining 12 nail, over the base nail on the left and right of it in such a manner that the heads of all the nails are towards the base nail. Place the head of the right nail on the base nail then the head of the left nail on the base nail, again the head of the right nail, then the head of the left nail, and so on, till you have placed all the 12 nails on the base nail.

5.         Now, place the fourteenth nail on the base nail in such a manner that its sharp end is towards the head of the base nail. In this way all the twelve nail will come between the base nail and the upper nail.

6.         Pressing both the base nail and the upper nail against each other and holding them with both you hand carefully place the entire set of nails at the mid print of the base nail fixed to the stand. Withdraw both your hands slowly. The pointed or sharp ends of the nails get lowered on both the left and right sides and their blunt and flat ends get entangled with one another. The entire set of nail resting on the base nail balances on the nail stuck to the stand. Surprising, isn’t it? 

Discussion : In this experiment the principle of centre of gravity plays its role. According to this principle, due to the weight of the inclined nails on both sides of the base nail the weight of the entire set-up acts below the balancing point. Thus, the entire set of nails balances comfortably. You may gently lower the nails on one side and then remove your hand. This makes the entire set-up quiver but it  does not fall down. 

Do and think a bit more : If you so desire, you may carefully remove some of the nails from both sides of the balancing point one by one. See how many nails you can remove without disturbing the equilibrium state.        





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