Magic Leaky Bottle

Concept: Pressure. Force is exerted on objects by air pressure.

Materials: 2 liter bottle

tape

pin or needle

water

pan

Directions:

1. Put two small holes (about the diameter of the lead in a pencil) on one side of the bottle, one near the bottom and the other about the middle of the bottle.

2. Put a piece of tape on each of the two holes.

3. Fill the bottle with water, you can dye the water in order to see it better.

4. Screw the cap back onto the bottle.

(During the demonstration)

5. Take the tape off the first hole closest to the bottom of the bottle. Observe what happens. (The water should not come out of the hole. Now unscrew the cap and the water should come out of the hole. Screw the cap back on again and the water should stop coming out again.

6. Uncover the next hole, observe what happens. The results may vary. Either nothing will come out of either hole or there will be bubbles of air going into one hole and the water leaking out of the second.

7. Unscrew the cap, observe what happens to each of the holes. This time there will be water coming from both holes. Which hole produces the stream of water that shoots out the furthest?

The bottom hole should have the water squirting out the furthest.

Introduction:

I am very upset boys and girls. You know what happened to me yesterday. I went to the grocery store. I was so thirsty. So I decided to buy this bottle of water. I went up to the cashier and my water cost me twenty dollars. The cashier told me that it was a "magic bottle" , hmmmmm.... I wonder why?

Explanation:

When the cap is on the bottle, the air pressure in the bottle is equal to the air pressure outside the bottle. Since the pressure is the same nothing comes out of the uncovered hole at first. When the cap is taken off, the water squirts out of the bottle. The water pressure in the bottle is greater than the air pressure on the out side of the bottle. The reason for this is because the weight of the water caused by gravity has a greater pressure then the air pressure outside of the bottle.

The weight of the water in the bottle causing pressure causes the water to shoot out of the lowest hole the farthest. This is because the height of more water above the hole has more weight and creates a greater pressure that the hole that is higher on the bottle.

Safety Precautions:

There are no chemicals used in this experiment. Just be cautious when poking the holes in the bottle.

Waste Disposal:

You can dump the rest of the water in the sink and you can throw out the bottle.

References: Unknown