GENERAL KNOWLEDGE

Detailed explanation-1: -What oxygen level is required to keep the candle burning? The candle was extinguished after 30 seconds when the air was made up with 18.8% oxygen. This shows that the candle flame requires an oxygen level of greater than 18.8% oxygen to remain alight.

Detailed explanation-2: -How Oxygen Candles Work. Oxygen is produced from a thermal, chemical reaction. Oxygen candles house a mixture of sodium chlorate, barium peroxide and iron powder; the oxygen-producing chemical is sodium chlorate. This chemical reaction requires a significant amount of energy input, hence the need for iron powder.

Detailed explanation-3: -The combustible material in a candle-or its fuel-is the wax. But before the wax can become fuel it first needs to get hot enough. To start that heating process, you first need to light the wick with another source of fire, such as a match. As the wick burns down the heat of the flame melts the wax around the wick.

Detailed explanation-4: -The physical aspect: the candle heats the air and expands it. This cancels the depletion of the oxygen temporarily and the water level stays down. When the oxygen is depleted, the candle goes out and the air cools. The volume of the air decreases and the water rises.