Final answer:
In a vacuum jar, a peep expands when the air molecules are removed and shrinks back when the air molecules are reintroduced.
Step-by-step explanation:
When the peep is placed in a vacuum jar, the air molecules are removed from the jar, creating a low-pressure environment. Without air molecules, the peep expands due to the decrease in external pressure. It becomes larger in size.
When the air molecules are reintroduced into the jar, the pressure inside the jar increases. As a result, the peep begins to shrink back to its original size. This is because the increase in external pressure compresses the peep.
It is important to note that the temperature of the boiling water is not directly related to the question about the peep in the vacuum jar.