Air Pressure Science Fair Project. If air has weight, it should exert pressure upon everything. Learn to create a barometer to measure air pressure!
Science Fair Project Idea : Does air press upon things? If air has weight, it should exert pressure upon everything; because the atmosphere extends many miles above the earth's surface.
Science Fair Experiment: Air Pressure Into a tin can which has a small opening, put a few spoonfuls of water. Heat the can until sufficient steam is formed to
drive out the air. Plug the opening in the can with an airtight stopper. As the can cools, the steam changes back to water and the space within the can
contains neither steam nor air and is called a vacuum.
What happens to the can ? Explain. Use a wide-mouthed bottle instead of
the can and in place of the stopper tie a piece of paper or still better a piece of
sheet rubber over the opening. Result ?
Conclusion ? Science Fair Project Idea: How Can One Measure Air Pressure? The amount of this Air pressure, which of course will also be the measure of the weight of the air over a certain space, may be found by repeating the experiment of Torricelli, a pupil of Galileo, made in 1643.
This was the first measurement made of air pressure. Science Experiment to measure Air Pressure Do NOT do this alone. Make sure you get an adult to do this for you carefully as mercury is toxic! Fill with mercury a glass tube about three feet long and closed at one end. Closing the open end with the finger to prevent the escape of the mercury, invert the tube and place the open end below the surface of mer-
cury in a dish. Now withdraw the finger and note the result. Question: What keeps the mercury in the tube above the level of the mercury in the dish?
If the tube has a cross section of one square inch, the weight of the mercury held above the level of the mercury in the dish will be about fifteen pounds. Therefore it may be stated that air exerts a pressure of about fifteen pounds per square
inch. Questions to answer: - Why must one end of the tube be closed?
- Where does the air press ?
- Why does the mercury not reach the top of the tube ?
The scale is in inches or centimetres. The apparatus used in this experiment constitutes the essentials of a mercury barometer. Since weather changes are accompanied and frequently preceded by changes n air pressure, the practical value of the barometer may be understood. Science Project Air Pressure Part 2 - Why is water not used in making barometers? From the last experiment we learn that the pressure of the air will hold up a column of mercury about 30 inches in height. Would a longer or shorter column of a lighter liquid be held up? Explain. Evidently, therefore, in selecting a liquid to be used in a barometer, its weight must be considered. Experiment for Barometers Into each of two beaker glasses put respectively equal volumes of mercury and water.
Lift the glasses. Which is the heavier? Put the beaker glasses containing the mercury and water on
the opposite pans of a balance and by the use of weights find out how much heavier one substance is
than the other. What is the Jesuit ?
The height of the mercury column is measured in centimeters, c, surface of mercury upon which air is pressing, a, screw
by which the mercury in the mercury cup is adjusted so that the surface (c) is at the zero point of the barometer tube, d, thermometer, e, screw for adjustment of a scale (vernier) by which the height of the mercury may be read more accurately, scale at top of mercury column.
If mercury is thirteen and one-half times heavier than water calculate the height of a column of water that may be
held up by the pressure of the air. Such a barometer was constructed by Otto von Guericke, the inventor of the air pump.
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