Question

A man is cooking two pans of boiling water. Both pans are made of steel, but one pan has a much thicker base than the other pan.The man usually puts a lid on his pans when he is heating water. Explain two ways a lid helps the water to reach boiling point more quickly.

Answer 1

Using a lid on a pan helps water boil faster by enhancing heat retention and increasing the pressure inside the pan, which lowers the energy required to reach the boiling point.

Step-by-step explanation:

When a man cooks two pans of boiling water, placing a lid on the pans helps the water reach the boiling point more quickly in two primary ways. First, heat retention is enhanced with a lid, as it prevents heat from escaping through steam. This conserves the energy within the system, thereby raising the water temperature more efficiently. Second, the lid creates a buildup of pressure inside the pan, resulting in an increased boiling point of the water. This buildup of vapor pressure means that less energy is required to bring the water to its boiling point, as the heat is contained within the pan rather than being lost to the atmosphere.

It is essential to understand that the buildup of vapor pressure can also have safety implications. If a vessel is sealed and unable to vent, the pressure can become too high and cause an explosion. Therefore, while a lid accelerates boiling by containing heat and increasing pressure, it is also necessary for the lid to have a way to release excess pressure safely.