Question

Why water have a concave miniscus

Answer 1

Answer:

Because water and oil don't mix. The miniscus that forms in a glass tube is caused by water adhesion to the polar molecules in the glass. The plastic is chemically similar to oil so it tends to repel water thus it pushes away the water where it contacts the tube. This makes it form an Inverted miniscus. Or In simple Words,

Due to hydrobhobic nature of most plastic vessels and due to surface tension water have concave miniscus.

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