Specifics of the Experiment
The container was 12 inches in diameter. Priestley turned it upside down to lock the air in and he placed it in the sunlight.
Contents of Container
Inside the container was a chunk of mercuric oxide being heated.
What question was he trying to answer?
Joseph, like many others, was curious as top why things burned. Why do things burn? What causes and allows them to burn? He experimented to find out.
What was Joseph's Hypothesis?
Why do things burn? What causes the mouse in the sealed glass jar to lose consciousness when under it for too long? Why did the plant give allow the mouse to survive longer when present?
Priestley had a mouse in a sealed jar and noticed that it would eventually collapse without air. He then put a mint plant inside of the jar and saw that it aroused the mouse. He realized that the plant somehow managed to freshen the air inside of the jar. On August 1,1774, Joseph had isolated the gas by heating mercuric oxide power and seeing that it released a gas that ignited and flame. Joseph collected a great sum of the gas and took a big whiff of it, not a waving waft, and described his breath as quite light and effortless.
When he concluded that Oxygen was the reason the mouse could survive in the jar with only a plant in it or occasionally opening the jar for fresh air, he found that the plant was giving the mouse "strength" or air. When the burning candle was inside the sealed jar there would be no air for the mouse to breathe. After a little while, the candle went out leaving behind smoke. But when the jar was not enclosing the candle in a sealed environment, the candle stay lit much longer. Joseph concluded that the fire needed some type of airborne in order to burn. He resulted in the fact that it was the air, or oxygen, that was keeping the candle's fire going. Joseph then put in a plant, and after a few minutes, the mouse had regained consciousness and was functioning normally.
Oxygen was the element that kept the fire going. In a sealed jar with a burning candle, there is no oxygen for the fire to absorb. The fire gives off heat which makes the air thin, and it also gives off carbon dioxide, which a living thing cannot survive off of, besides plants. Plants can take in the carbon dioxide to survive and release oxygen, but animals such as humans and mice take in oxygen and release carbon dioxide, humans and mice cannot take in carbon dioxide consistently for a long period of time and survive.