Ask A Scientist Chemistry Archive

Question:
Why, when you put water in a glass beaker, it forms a meniscus curve, but
when you put water in a plastic beaker, it doesn't?
 mvhs

Answer:
Adhesion is responsible for a meniscus and this has to do in part with
water's fairly high surface tension.  Water molecules are attracted to
the molecules in the wall of the glass beaker.  They'll travel up the
glass as far as water's cohesive forces will allow them.  Cohesion is
an intermolecular attraction between like molecules (other water molecules
in this case).  All according to Chang's _Chemistry_.  Water molecules
just aren't attracted to plastic molecules as much as glass molecules.
-Joe Schultz