|
|
|||||||||||||||||||||||||||||
  |
|||||||||||||||||||||||||||||
Getting Hotter = Getting BiggerNow you need to think about states of matter a little bit. We'll start with gases. The idea behind thermal expansion is that gases expand as the temperature increases. If you have a balloon and you heat up the contents, the balloon will get larger. Scientists use the term ideal gas law to describe this activity.Liquids expand and contract, too, but there is a lot less change in their volume compared to gases. Scientists say they have a smaller thermal expansion coefficient. As you can probably figure out, solids expand and contract the least of all the states of matter. A formula describes how much a piece of matter will change its volume. The formula is used all over chemistry and physics and compares the changes in volume to the changes in temperature of a system. [Insert Formula Graphic Here] V is the final volume, Vo is the initial volume at 0 degrees Celsius, Beta is the expansion coefficient and t is the temperature of the system. The expansion coefficient is a value for each piece of matter. It is a unique value, just like specific heat capacity. Two examples of coefficients are air at .00367 and alcohol at .000112. Things Shrink When They get ColdThe opposite of expansion is contraction. If things expand with the addition of energy it makes sense that they contract when energy is removed. If you remove enough energy from a gas it will become a liquid. Liquids can turn into solids. What happens when you remove almost all of the energy from a system? Scientists use the terms absolute zero to describe a system that has no energy. When there is no energy in a system, all molecular motion stops. It seems that even the atoms begin to merge at these low temperatures. Physicists have recently created the Bose-Einstein state of matter that has a small group of atoms with nearly all of the energy taken out of the system.
|
|
||||||||||||||||||||||||||||
Go for site help or list of physics topics at the site map!©copyright 1997-2007 Andrew Rader Studios, All rights reserved. Current Page: Physics4Kids.com | Thermodynamics & Heat | Expansion |
|||||||||||||||||||||||||||||
|
|
|||||||||||||||||||||||||||||