Community Outreach
Ask the Scientist!
Are you a K-12 student with a question about a science, technology, engineering, or math topic?
Send your question to a scientist!
Fill in the boxes below with your question and a little information about yourself.
Each month our scientist will select one question from the mailbox and post an answer here. You can view previous questions and answers, by date or by subject, in the archives. If your question isn't answered this month, stay tuned! It could be used later!
![]()
This month's question
Q: How many phases of matter are there? --Ethan, Grade 7, Carlisle, MA
A: Matter is material or stuff, everything from us to plastic toys to water and air. As you heat or cool matter, it passes through four different phases:
1. Solid. When matter is relatively cold, the tiny pieces that make up the matter (atoms or molecules) all huddle close together, just as people or pets may do when they are very cold. The atoms or molecules are too cold and huddled too close together to move around, so the matter is a solid chunk. Water that has frozen and become ice is a good example of a solid.
2. Liquid. When matter is somewhat warmer, its atoms or molecules still stay fairly close together, but at least they can move around. Since its component atoms or molecules can slide past each other, the matter is a liquid that can flow from one place to another, change shape, or break into droplets. Normal water is a good example of a liquid.
3. Gas. When matter becomes warmer, its atoms or molecules do not want to be very close to each other and prefer to spread out, just as people do on a hot day. Thus the matter becomes a gas, with one atom or molecule over here, another one over there, and the rest spread out all over the place. Water that has been heated to become steam is a good example of a gas.
4. Plasma. When matter is heated to very high temperatures (thousands of degrees), not only do its atoms or molecules travel around separately like a gas, but even the electrons that are normally trapped inside the atoms or molecules want to be on their own. Electrons have a negative electric charge, and when they leave their atoms behind, the atoms are left with a positive electric charge and are called ions. This super-hot “gas” of electrons and ions is called a plasma, and is the fourth state of matter. Good examples of plasmas include the sun and those clear glass plasma globes filled with sparks that are often sold at Spencer’s in malls and at other novelty stores.
For simple experiments you can do at home, see:
Learn the States of Matter with a Snowman
Solar Purifier
TLC's Science Projects for Kids: States of Matter
Kid's Guide to the States of Matter
September 2012
Questions and Answers
|
Questions and Answers
|
||
top of page

