| MadSci Network: Chemistry |
This is actually a more difficult question that it seems, and it stumped a few PhD's that I asked. A gel is formed when molecules bond with neighbors in long, interlaced chains. The result is a material with a measure of strength and some rigidity, but which is also flexible.
The molecules are not, however, held rigidly next to each other, as in a true solid. We believe that if you were to leave a block of jello, for example, sitting on a tabletop for a long time, it would flow under the influence of gravity. Instead of being a solid, jelly or jam should instead be thought of more as very viscous (thick) liquids.
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