Which of the fact is not due to surface tension

Options

A. Dancing of a camphor piece over the surface of water
B. Small mercury drop itself becomes spherical
C. A liquid surface comes at rest after stirring
D. Mercury does not wet the glass vessel

Explanation

To determine which fact is not due to surface tension, we can analyze the options provided in the question. Here’s a step-by-step solution:

### Step 1: Understand Surface Tension
Surface tension is a property of liquids that causes them to behave as if their surface is covered with a stretched elastic membrane. It is responsible for various phenomena, such as the formation of droplets, the ability of some insects to walk on water, and the rise of liquids in capillary tubes.

### Step 2: Analyze Each Option
We need to evaluate each option to identify which one is not related to surface tension.

1. **Option A**: "A small mercury drop itself becomes spherical."
- This phenomenon is due to surface tension. Mercury has a high surface tension, which causes it to form a spherical shape.

2. **Option B**: "Dancing of the paper clip over the surface of the water."
- This is also due to surface tension. The surface tension of water allows the paper clip to float despite being denser than water.

3. **Option C**: "A liquid surface comes at rest after stirring."
- This phenomenon is primarily due to viscosity. When a liquid is stirred, it takes time to settle back to a calm state, which is influenced more by the liquid's viscosity than by surface tension.

4. **Option D**: "Mercury does not wet the glass."
- This is due to surface tension as well. Mercury has a high surface tension and does not spread out on glass, leading to a non-wetting behavior.

### Step 3: Identify the Correct Answer
From the analysis above, we can conclude that **Option C** ("A liquid surface comes at rest after stirring") is not due to surface tension but rather due to viscosity.

### Final Answer
The fact that is not due to surface tension is **Option C**.

---