2. Expansion and Contraction
When the temperature of a material increases, the
particles move faster.
These particles tend to spread out more.
This causes materials to expand or spread out as
they get hotter.
3. Expansion and Contraction
The opposite happens when the temperature of a
material decreases.
Cool materials tend to contract – shrink.
The material’s particles tend to slow down and stay
closer together.
4. Expansion and Contraction
Gases are affected most with changing temperature,
but solids and liquids are affected too.
Water is the exception to this.
Water expands when frozen, unlike most other
liquids that contract (shrink) when cooled.
5. * How is Expansion and
Contraction Useful?
Thermometers have liquid mercury or colored
alcohol in them. The liquid expands or contracts
with changes in temperature and moves up or down
the tube. The position of the liquid in the tube gives
the temperature.
6. * How is Expansion and
Contraction Useful?
The solid materials that make up a bridge or
sidewalk expand when warmed. If the sections are
assembled tightly on a normal day, the will expand
against each other on very hot days. This expansion
can cause cracks to form. To guard against this
problem, engineers leave some space between
sections and fill it with a flexible material.
