My PBL Project

Key words: Gravity, Center of Mass, Center of Gravity and Balance

Introduction: In this experiment we will be dealing with center mass and center of gravity. The objective is to get 11 nails to balance on a single nail that is standing straight up from a block of wood. To do this you have to have an even distribution of weight and by using center of mass. In physics center of mass is the unique point where the weighted relative position of the distributed mass sums to zero. Using this strategy you can get the whole 11 nails to balance on the nail head of one nail.

Principle: The principle of this experiment to find the center of gravity of an object before you can get an abject to balance on top of another object no matter how smaller the point of balance may be. Gravity pulls an object down as if all its weight was concentrated on one point, the center of gravity. The stability of the nails depends on the center of gravity being below the point where it sits on the bottom nail. If there is too much weight on either side of the balancing nail structure, left or right the nails will become unstable and fall apart.

Materials:

• 12 identical nails with flat heads (10 penny size)

• A block of wood

• Hammer

• Safety Goggles

Procedure:

1. Put on safety goggles

2. Get the hammer block of wood and nail, hammer the nail into the wood until it is standing up strong and straight. ( see picture above)

3. Get the remaining 11 nails, the objective is to get all the nails to balance on top of the nail head of the nail hammered into the wood.

4. Lay one nail horizontally flat against a desk/table.

5. Get another nail and lay it down against the first nail in step 4. Lay it down by the nail head.

6. Get another nail and repeat the process only lay it in the opposite direction of the last nail.

7. Repeat this step until there is only one nail left.

8. With the last nail lay it down across the structure vertically but facing the opposite direction of the nail in step 4.

9. It should look like this>>>>>

10. Now lift up the nails by holding the tips on the top and bottom nail and try to balance it on the nail hammered into the block of wood.>>>>

11. Your end product should look like this>>>>>>>>

Safety Regulations: Wear when you are handling the nails and have adult supervisions when you are using the hammer.