Matt

Matthew Dawson

Topic: Denisty and Pressure. Introduction: Denisty= Mass/Volume. Objects float or sink depending on whether they are less or more dense than water. A submarine which both floats and sinks, does so by adjusting the amounts of water and air inside it's body. In the following procedures you will observe how air can be used to increase or decrease the denisty of an object, causing it to float or sink. Time Needed: 30 minutes. Matriels: 2 eyedroppers, 50 cm plastic aquarium tubing, modeling clay, 100-mL graduated cylinder, empty plastic shampoo or dishwashing detergent bottle, Large fish tank or bowl ( at least 2 gal). Procedure: Part A, 1. Fill the graduted cylinder completey with water. 2. Fill the eyedropper 3/4 full with water. 3. Place the eyedropper in the water so that it floats with the bulb. The dropper should just barrelly float in the cynalinder,so only the top of the bulb is showing.If the dropper is floating to high, add some water to it ; if it sinks, remove the water. 4. Place your hand over the top of the cyliander and apply light pressure so that the top is compelety sealed off and no water spills over. 5. Press your palm agianst the cyliander and observe what happens.

Matthew Dawson Science Fair Topic __ Movement of a Submarine __ My topic for this year’s science fair is the movement of a submarine. This subject has to do with physical science. Density and Pressure has a lot to do with this experiment. (Density = Mass/ Volume). A submarine can both float and sink; which does so by adjusting the amounts of water and air inside its body. In the following procedures you will learn how air can be used to increase or decrease the density of an object, causing it to float or sink. There are some background facts supporting the project. A famous scientist named Archimedes **discovered density. Archimedes discovered density by sitting in a bath full of water, and realized the water that spilled was equal to the space he took up in the bath.** In 1643, E vangelista Torricelli, a Mathematician who had studied with Galileo, became convinced that the weight of the air pushing on the pool of water at the foot of the mineshafts had something to do with the height to which water would rise. He designed and had his assistant, Vincenzo Viviane; carry out an experiment to test the idea. Vivian took a 6 foot long glass tube and filled it with mercury. Then he placed his finger over the opening and inverted the tube into a bowl of mercury with the sealed end up, and measured the resulting height of the mercury column. Mercury, with a density of 13.6 g/ml. is much denser than water. Torricelli realized that if he used mercury he would not have to use such a long tube. If he used water, he would have needed a column of water 13.6 times that of mercury, or about 32 to 33 feet high.  Some more information about density is that there is a very common instrument for the direct measurement of the density of a liquid. It is the [|hydrometer], which measures the volume displaced by an object of known mass. A common laboratory device for measuring fluid density is a [|pycnometer] ; while a related device for measuring the absolute density of a solid is a [|gas pycnometer]. Another instrument used to determine the density of a [|liquid]   or a [|gas]  is the digital density meter - based on the [|oscillating U-tube]  principle. Some more information on air pressure is that air pressure is a measure of the weight of a column of air on the earth's surface, or on us for that matter. That is important because that great mass of air contains the oxygen we breathe which keeps us alive. It's a pretty subtle thing too. If we have 14.7 lbs pressing down on every square inch of us, why don't we feel weighed down? Three reasons - first it's equally distributed all over us, it's much less than the force of gravity, which we do feel, and we also don't feel crushed because the pressure inside our lungs is the same as the air outside, which we breathed in.  My project: Topic: Density and Pressure. Introduction: Density= Mass/Volume. Objects float or sink depending on whether they are less or more dense than water. A submarine can both float and sink; which does so by adjusting the amounts of water and air inside its body. In the following procedures you will observe how air can be used to increase or decrease the density of an object, causing it to float or sink. Time Needed: 30 minutes. Materials: 2 eyedroppers, 50 cm plastic aquarium tubing, modeling clay, 100-mL graduated cylinder, empty plastic shampoo or dishwashing detergent bottle, large fish tank or bowl (at least 2 gal). Procedure: Part A: 1. Fill the graduated cylinder completely with water. 2. Fill the eyedropper 3/4 full with water. 3. Place the eyedropper in the water so that it floats with the bulb. The dropper should just barely float in the cynalinder, so only the top of the bulb is showing. If the dropper is floating to high, add some water to it; if it sinks, remove the water. 4. Place your hand over the top of the cylinder and apply light pressure so that the top is completely sealed off and no water spills over. 5. Press your palm against the cylinder and observe what happens.