Boiling water - amount of steam

[wasia]

Hello!

There is an observation I have made when boiling water - amount of steam getting out of the kettle increases when the heating is turned off. Could anyone help to explain that?

The experiment goes like this. Take a kettle, start heating the water. The amount of the steam getting out increases (the kettle has a small hole at the top of it). When the water approaches the boiling point, the steam is getting out of the kettle at an impressive rate. However, if the heating is turned off (before or after boiling - does not matter) the amount of steam increases even further.

I wonder if
a) I am unable to judge the amount of steam accurately.
b) The form of the kettle (tested on 2) is relevant.
c) There is a good thermodynamical explanation.

Thanks.

 

[Mapes]

This is a common observation. What we're calling "steam" here is condensed water droplets (technically, steam is invisible water vapor). When you turn off the heat, the water vapor leaving the water surface condenses sooner, and the amount of "steam" therefore increases.

 

[astrokreng]

Hello! Thank you for sharing your observation. I can provide a possible explanation for the increase in steam when the heating is turned off. This phenomenon can be explained by the relationship between temperature and pressure in a closed system, such as a kettle.

When the water is heated, it reaches its boiling point and starts to vaporize, creating steam. As more heat is applied, the temperature of the water and steam increases, leading to an increase in pressure inside the kettle. This pressure pushes the steam out of the small hole at the top of the kettle.

When the heating is turned off, the temperature inside the kettle starts to decrease, but the pressure remains high. This is because the steam is still present inside the kettle and exerts pressure on the water and walls of the kettle. As a result, the steam continues to escape through the hole, leading to an increase in the amount of steam being released.

The shape and design of the kettle may also play a role in this phenomenon. A wider opening or a different placement of the hole may affect the rate at which steam escapes, but the overall principle of temperature and pressure remains the same.

I hope this explanation helps to clarify the increase in steam when the heating is turned off. If you have any further questions, please feel free to ask. Thank you for your interest in science!