States of Matter 4

"It may be real, but it's pretty boring," Stef responded with a smile.

After a moment, a questioning look came over her face.  "You know, I think the states of matter is part of the first chapter."  And, sure enough, after she went back to her book, the first chapter did have a section on the three states of matter: gases, liquids, and solids. Stefanie took out a blank notebook she had bought for the class and took her first notes.

Gases: spread out to fill their containers, don't have their own shape, you can compress or expand them, atoms and molecules relatively spread out.

Hmmm.  She should probably put down somewhere what atoms and molecules are.  She knew from high school science, but they were a little hard to define.  Down at the bottom of the same page she wrote down the words:

Atoms: the most basic building blocks of matter (=stuff), the smallest you can divide things with them keeping their basic properties.

Molecules: combinations of atoms

That seemed good enough.  Then she returned to liquids and gases.

Liquids: take on the shape of their containers but you can't compress or expand them, atoms and molecules closer together than gases, but not as compact as solids

Solids: have their own shape and you can't compress or expand them, atoms and molecules more compact than liquids or gases

"There," Stefanie said out loud to herself.  "Not interesting, but not particularly hard either."

She wrote one more paragraph under her definition of solids: "If you add enough heat to a solid, it will eventually become a liquid.  If you add enough heat to a liquid, it will eventually become a gas.  If you cool down a gas enough, if will eventually become a liquid.  If you cool down a liquid enough, it will eventually become a solid.  This is true of everything.