Correct Option
The correct option isLiquids exert pressure on the walls of the container.
Explanation
The phenomenon illustrates the concept of hydrostatic pressure. Fluids (liquids and gases) exert force on all surfaces they are in contact with, including the base and the walls of the container, due to the weight of the fluid column.
Option Analysis
- The rubber sheet has a high density. is Incorrect: The density of the rubber sheet is a material property unrelated to the mechanical bulging effect. While the density of the liquid affects the amount of pressure, the bulge itself demonstrates the existence of pressure, not the density of the sheet.
- Atmospheric pressure acts on the container from the outside. is Incorrect: Atmospheric pressure acts on the container and the rubber sheet from the outside, pushing inward. For the sheet to bulge outward, the internal pressure exerted by the liquid must overcome the external atmospheric pressure.
- Liquids exert pressure on the walls of the container. is Correct: The liquid inside the container possesses weight due to gravity. This weight translates into pressure that acts in all directions, not just downwards. The outward bulging of the rubber sheet on the side proves that the liquid exerts lateral pressure on the walls of the container.
- The rubber sheet absorbs the liquid and expands. is Incorrect: The bulging is a mechanical deformation caused by the force exerted by the liquid. It is not due to the rubber absorbing liquid or undergoing thermal expansion.
Key Takeaway: Liquids exert pressure on the walls of their container. This pressure acts perpendicular to the wall surface and increases with the depth of the liquid.