Kari Kelly
Principle(s) Illustrated
Definition of Boiling
Air Pressure
Vapor Pressure
PS1-A
The structure and interactions of matter at the bulk scale are determined by electrical forces within and between atoms.
PS2-B
Attraction and repulsion between electric charges at the atomic scale explain the structure, properties, and transformations of matter, as well as the contact forces between material objects.
Prior knowledge & experience:
Students know that water boils when enough heat is added. Students know that boiling water is hot.
Root question:
How can we make water boil?
Target response:
The boiling point is the temperature at which the vapor pressure of a liquid equals the external pressure surrounding the liquid. Therefore, the boiling point of a liquid depends on atmospheric pressure. The boiling point becomes lower as the external pressure is reduced.
Common Misconceptions:
Water must be hot to boil. Boiling is directly related to the amount of heat added.