Name: Shaly J.
Date: May 2004
What is a pseudo solid?
As far as I can determine, "pseudo solid" has no specific meaning. It is not
a real "thing." It is a word that is used by scientists or engineers when
they talk to each other and try to understand the way materials really
In science and engineering, especially engineering, it is not possible to
know things exactly. Instead, engineers "approximate" what they are
studying using a simpler picture. For example, the way fuel burns inside a
jet engine, or the way plastic flows when it is melted. These events are
difficult to understand because they are really very complicated when you
try to measure them very accurately. So engineers try to understand these
examples in a simpler manner. If your field of research is about something
nearly solid, then you might call it a pseudo solid. For example, some
colloid materials (mixtures of solid and liquid, like thick paint) are
solid. These mixtures do not flow. Blobs of this material aren't very
strong and if you push the blob it will start to flow. Some people call
this a pseudo solid because the a solid turns into a liquid.
A paste mixture of starch and water will flow, but if you hit it fast it
becomes hard. This is not a pseudo solid. Engineers simply call it a
Some people refer to glass or plastic as a "pseudo solid" when they want to
say that these materials sometimes have properties that are not perfectly
Click here to return to the Engineering Archives
Update: June 2012