posted by Miley on .
I looked in my book and I can't find the answers to these questions! Can anyone help me? :)
Question #1: Why do liquids in a graduated cylinder form a meniscus?
Question #2: Give three examples of amorphous solids. I have glass, can anyone give me two more!
Thanks :) !
Without getting into a discussion about adhesive and cohesive forces, the water wets the inner wall of the graduated cylinder and capillary action pulls the water upward on the glass surface. The center of the water, however, does not have this capillary action with the glass surface. Those molecules in the central section are pulled inward by intermolecular forces (hydrogen bonding in the case of water) and they tend to pull the water molecules inward. So the upward pull at the glass surface and the inward pull on the molecules in the central part of the meniscus, makes the meniscus. It looks, more or less, like this (but I can't draw a curve), '-'. By the way, not all liquids do this. Mercury, for example, a liquid, does not wet the surface of glass and the meniscus is like that of water but upside down.
Examples of amorphous solids are glass, plastic, leather, cotton candy.