This happens due to the water cycle in action, specifically the processes of evaporation and condensation. Here's a breakdown:

1. Evaporation: The plant's leaves release water vapor into the air through a process called transpiration. This is like the plant "breathing" and releasing moisture.

2. Trapped Moisture: The glass jar traps the water vapor released by the plant, creating a humid environment inside the jar.

3. Condensation: As the warm, moist air inside the jar cools against the cooler surface of the glass, the water vapor in the air changes back into liquid water droplets. This is why you see water droplets on the walls of the jar.

In simpler terms: The plant sweats, the moisture gets trapped, and the cool glass makes the moisture turn back into tiny drops of water.