Question

Give a reason for the following:

An empty tumbler lowered into a glass beaker containing water, on tilting shows bubbles of air coming out, but when not tilted, no bubbles are seen.

Answer 1

This is because, when we tilt the glass tumbler, the water enters inside it, which leads to the pushing of the air out of the glass tumbler. So, air comes out in the form of bubbles in the water present in the glass beaker. This is because when the tumbler is not tilted, the water pressure is the same all around the mouth of the tumbler. But, when tilted, the water pressure is higher on the lower side of the tumbler. This high pressure pushes the air from one end, and the bubbles are seen in the water.

Hence, an empty glass tumbler lowered into a glass beaker containing water, when tilted, shows bubbles of air coming out, but when not tilted, no bobbles are seen.