Tuesday, December 14, 2010

Candle & jar

Experiment from Ania&Jessika

Necessry components:
plate, water, small candle, glass vessel (example a jar), matches
Description of the method of execution:
We pour water to the plate. In the middle ofthe plate we put a candle and light it.We cover the burning candle with the jar so that the outlet is submereged in water. We wait until the candle goes out (oxygen consumption as a result of burning of the candle) observing the water level rising in the jar.
During the burning of the candle oxygenis consumed. Oxygen is strictly reqired for combuston, so after firing up the oxygen in the jar candle goes out. Lack of oxygen in the jar is the cause of the underpressure in the jar. Due to the pressure difference between pressure in the jar and the atmosphere(which is greater), water is pulled into the interior of the jar.
In addition, burning the candle heats the gasinside the jar. The heated air expands while increasing the pressureinside the jar. Due to the pressure difference (between the gas pressure inside the jar and atmospheric pressure) of air comes out of the jar. After the candle goes out the gas temperaturein the jar gradually decreases, causin reduction in pressure in the jar and pulls the water inside.

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