Background
Matter undergoes phase change when heated of cooled. Phase change therefore is accompanied by energy exchange and transformation. When phase change takes place in a closed container, changes in the physical properties and characteristics also accompany it.
The following videos of different demonstrations all have something to do with gaseous behavior.
Resources:
Core States of Matter page on my homepage. This page contains three PowerPoint slides on the relationship between state and energy of a substance, kinetic theory and gas laws.
The Discrepant Events
Demo 1.
A coin with some saliva is placed at the mouth of a wine bottle containing some wine. The bottle then is placed inside a beaker with hot water. Watch the video to see what happens next.
Demo 2.
In this Discrepant Event, a soft drink can with a little bit of water is heated over a Bunsen burner until steam starts coming out of the opening. It is then quickly inverted over a trough of water. Watch the video to see what happens next.
Demo 3.
A conical flask with a little bit of water and a peeled hard-boiled egg on its mouth is heated over a Bunsen Burner until the water starts boiling. Then flask is taken off the tripod stand and allowed to cool down on the bench. Watch the video to see what happens next.
Your task: Explain what happened in each case.
Extension task: Describe how you would get the egg out in one piece without breaking the flask.
Concepts involved:
- temperature, energy/heat transfer, evaporation/boiling, pressure, atmospheric pressure, cooling, condensation (additional concepts: vacuum, expansion, contraction, number of gaseous particles).
