Explain why water wets glass, mercury forms a convex meniscus, and mercury forms spherical drops on glass.

Here are the scientific reasons for the given statements:

a) Water wets glass because the adhesive forces between water molecules and the glass surface are stronger than the cohesive forces between water molecules themselves. This causes the water to spread out and adhere to the glass.

b) The mercury meniscus is convex because the cohesive forces between mercury atoms are much stronger than the adhesive forces between mercury and the glass surface. This strong cohesion causes the mercury to pull away from the glass, forming a convex shape.

c) Small drops of mercury form spherical drops when in contact with a clean glass plate due to its high surface tension and strong cohesive forces. Mercury minimizes its surface area to volume ratio, and a sphere is the shape with the smallest surface area for a given volume, especially when adhesive forces with the surface are weak.