In #MESExperiments 46 I demonstrate the famous burning candle - rising water experiment, which shows how an enclosed flame can cause the pressure to drop, thus forcing water to rise upwards. The mainstream science explanation is as follows:
The flame results from a combustion reaction between the candle wax and oxygen in the air: 2 O_2 + CH_4 = CO_2 + 2 H_2O
Twice as much oxygen is burned than carbon dioxide is released, causing a decrease in air volume BUT this is temporarily countered by the increase in temperature, thus the water level stays constant.
As the oxygen is depleted, the flame goes out causing a temperature drop, thus the volume and pressure drop suddenly as well.
The higher atmospheric pressure outside the cylinder causes the water to rise inside the lower pressure cylinder.
Candle flame combustion involves paraffin wax reacting with oxygen in the air, after first reaching the chemical reaction activation energy via the lighter: https://x.com/i/grok/share/A4sAXWSRvKka9DiXOsQgFCNok
Timestamps
Placing candle on the plate and pouring a cup of water: 0:00
Lighting the candle with a lighter: 0:05
Placing the graduated cylinder over the candle: 0:13
Air bubble is pushed out (not always the case) and the flame goes out and water starts to rise: 0:25
Entire candle is lifted upwards in water: 0:35
Removing the cylinder with a small plate to avoid it spilling: 0:42
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