Why does the candle flame go out and water level rises when covered with an inverted glass?

Question:

What causes the candle flame to extinguish and the water level to rise when a burning candle is covered with an inverted glass?

Answer:

The candle flame goes out and the water level inside the glass rises because the burning candle consumes oxygen and produces carbon dioxide and water vapor.

When a candle burns, it undergoes a chemical reaction called combustion. This reaction produces heat, light, carbon dioxide, and water vapor. As the candle burns, it consumes oxygen from the surrounding air to sustain the combustion process.

When the inverted glass is placed over the burning candle, it creates a closed system. The heat from the candle causes the air inside the glass to expand, creating a low-pressure area. This low pressure causes air from the surroundings to rush in, resulting in a flow of air known as convection.

According to the ideal gas law, the pressure of a gas is directly proportional to its temperature and the number of gas molecules present. As the candle burns, the temperature of the gases inside the glass increases, and the production of carbon dioxide and water vapor increases the number of gas molecules. This leads to an increase in pressure inside the glass.

The increased pressure inside the glass pushes the water level up. Eventually, the candle flame goes out because it consumes all the available oxygen inside the glass, thus halting the combustion reaction. As the gases inside the glass cool down, their temperature decreases, causing them to contract and the water level inside the glass gradually returns to its original position.

This phenomenon demonstrates the principles of gas laws and how the burning candle affects the gases inside the closed system created by the inverted glass, leading to the extinguishing of the flame and the rise in water level temporarily.