What exactly are the states of matter? – Tammy, 7, Miami

Dear Tammy,

No matter if you are a cat, a person, or a snowball, we have one thing in common: We are all made up of matter. Most everything that we see in our world is made of matter.

As a matter of fact, my friends and Washington State University researchers Maren Mossman and Peter Engels are also curious about it. They gave me a great idea to help us investigate the three most common states of matter: liquid, solid, and gas.


It’s been pretty snowy where I live, so I took a snowball and put it in a cup. You can try this at home, too. If you can’t find snow in Florida, an ice cube will also work.

Frozen water is made up of very small particles called atoms. The particles that make up the frozen water don’t move around a lot. They are very orderly and pretty still.

If we heat up the ice, the water particles will spread out and move around. In a liquid, water particles travel freely in whatever space contains them.

If you let your cup of water sit for a few days and add more heat you may notice the water will disappear. The water is still around, though. It’s just transformed. It has become a gas called water vapor and drifted off into the air.

All these forms of water are made up of the same matter. In water’s case, that’s two hydrogen atoms and one of oxygen. But depending on the temperature and how the particles are arranged, they will be in different states.

If you’ve ever seen lightning strike, you’ve actually observed another state of matter. That’s a plasma. Plasmas are found in nature, but usually under extraordinary conditions. It’s what makes up our super hot sun. It’s also what we see when we look at parts of space where stars are born or when we watch the northern lights.

We have solids, liquids, gases, and plasmas. But wait, there are other states of matter that do not form naturally. Scientists like my friends Mossman and Engels can make one of them in their lab.

If we thought ice was cold, then this state of matter called Bose-Einstein condensate is way colder. Water freezes at 0 degrees Celsius. The matter they make in their lab is nearly -273 degrees Celsius. That’s about as cold as you can make anything. It is the coldest known state of matter—even colder than temperatures in outer space.

When we look at matter, scientists say it behaves similarly to light. Meaning that matter is both a particle and a wave at the same time. At regular temperatures, we can’t see matter’s waviness. The waves are too small.

But when we cool matter down to really low temperatures, we can actually see it acting like a wave. In this way, we can better observe and learn about the nature of matter. Now, that’s some super cool science.

Sincerely,
Dr. Universe