What happens to the air particles in the bubble when you pull up on the plunger

The air particles in the bubble are forced to expand when we pull up on the plunger.

Explanation:

Pulling creates a large amount of volume, when the volume of the air bubble is increased, air particles inside the bubble tries to accumulate all of the volume by expanding the size of the bubble. Since according to Ideal gas law,

P V = n R T

where P = Pressure of the gas

V = Volume of the gas

n = No. of moles

R = Boltzmann's constant

T = Temperature

We can observe that pressure is inversely proportional to the volume of the gas. Therefore, when we pull up the plunger, the volume of the air bubble is increased and the pressure inside it is decreased.