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Unit 13: Thermodynamics Page 14
waves as light. Your ears perceive temperatures. There are three
certain frequencies of longitudinal common states of matter; solid,
waves as sound. Your skin, mouth liquid, and gas.
and tongue can perceive thermal
There is another state of matter
energy as hot or cold. What a
called plasma but it is not common
magnificent energy sensing
on Earth. Plasma is a highly
instrument you are!
energized gas. It is used in
florescent lights. I’m going to
Thermal Energy
assume you know a bit about
Objects whose molecules are solids, liquids and gasses so I
moving very quickly are said to won’t go into much detail about
have high thermal energy or high them here (see Unit 3 and 8 for
temperature. The higher the more information).
temperature, the faster the
What I do want
molecules are moving. You may
to talk about is
remember that temperature is just
what happens as
a speedometer for molecules.
temperatures
You may have asked yourself the change in a
question, “So, if everything is substance. Let’s
made of molecules, and these take one of the neatest substances
molecules are often speeding up on the Earth, water. Water is quite
and slowing down...what happens special since it can be in its solid,
to the stuff these molecules are liquid and gas state at relatively
made of if they change speed a “normal” temperatures. It’s quite
lot? Will my kitchen table start special for a variety of other
vibrating across the room if the reasons too, but we’ll leave it at
table somehow gets too hot?” that for now.
No, it’s pretty unlikely that your Pretend we have an ice cube on a
table will begin jumping around the frying pan (poor ice cube). Right
room, no matter how hot it gets. now the water is in a solid state.
However, some interesting things It’s holding its shape. The
do happen when molecules change molecules in the water are held
speeds. together by strong, stiff bonds.
These bonds hold the water
Changes of State
molecules in a tight, very specific
Matter has a tendency to hang out pattern called a matrix.
in fairly stable states under normal
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