Can a glass be filled to above its brim with out spilling?

Question

Can a glass be filled to above its brim with water without the water spilling over the edge? Try it and see. Explain your observations.

Answer 1

no

Answer 2

Yes, but just a tiny little bit.

Try it! (add drop by drop with a tiny pipette)

It is because of surface tension. You will see a tiny round edge forming at the rim.

Answer 3

At the top of the glass, the 'Surface Tension' of the water when it's very carefully added to the full glass, will form an inverted 'Meniscus' (Convex surface) which protrudes above the rim of the glass.

(Water in a partly filled glass, forms a 'Concave' (downward curve) 'Meniscus' due to the 'Adhesive Forces' of the water on the glass being greater than the 'Cohesive Forces' of the glass on the water).

(Mercury will form a Convex (upward curve) 'Meniscus' as the above forces act in the opposite way).