Exploring the Science of Boiling Water: Why Does It Not Boil?

[jlaugh87]

Homework Statement

If you suspend an open-topped container of water in a pot of boiling water, water in the inner container will reach 100 degrees C but will not boil. Why is this?

Homework Equations

The Attempt at a Solution

 

[HallsofIvy]

Darned if I know! The question, as stated, makes no sense to me. The water in the open-topped container will eventually just mix with the other water, reach 100 degrees C and boil! Are there time constraints on this? Are you assuming that the heat causing the water in the pot is removed? In that case I suppose there are some conditions on the comparative size of the two containers and original temperature of the water in the container to allow the latent heat in the pot to cause an average temperature of 100 degrees for all the water but not sufficient additional heat to make up the 'heat of boiling' for all the water. But I don't think that's what's meant here.

 

[ogb p]

The reason why the water in the inner container does not boil is due to a phenomenon called superheating. This occurs when water is heated above its boiling point without actually boiling. In this case, the water in the inner container is heated by the steam from the boiling water in the pot, but since it is not in direct contact with the heat source, it does not have enough energy to overcome the surface tension and form bubbles, which are necessary for boiling to occur. Additionally, the inner container may also be made of materials that are not conducive to boiling, such as glass or metal, which can further prevent the formation of bubbles. This phenomenon is not exclusive to water, as other liquids can also experience superheating under certain conditions. It is important to note that superheated water can be dangerous, as it can suddenly boil and cause an explosion when disturbed. To avoid this, it is recommended to use containers specifically designed for boiling liquids and to handle them with caution.