States of Matter
Solids, liquids and gases differ in how particles are arranged and move.
About this topic
The three common states are solid, liquid and gas. In solids, particles are packed tightly in fixed positions and vibrate, giving a definite shape and volume. In liquids they are close but can slide past each other, so liquids take the container's shape with a fixed volume. In gases they are far apart and move freely, filling the container.
Changing temperature or pressure can move a substance between states. Adding heat raises the particles' kinetic energy until they overcome the attractions holding them together: melting turns solid to liquid, boiling or evaporation turns liquid to gas, and sublimation skips the liquid stage, as dry ice does. Cooling reverses the process through condensation and freezing. During these changes the temperature stays steady while energy goes into breaking attractions.
Picture a block of ice in a pan on a stove. At first the water molecules only vibrate in a rigid lattice; as heat arrives they break free and flow as liquid water; at 100 degrees Celsius they escape as steam and spread through the kitchen. Applications include refrigeration, steam engines, and freeze drying of food.
A frequent mistake is thinking particles themselves expand or melt. In fact the particles stay the same; only their spacing and motion change. Remember also that gases are compressible, liquids almost are not, and solids hold their shape.
Key ideas
- Solids keep shape and volume
- Liquids flow but keep volume
- Gases fill any container
Quick check
Use cases: where States of Matter helps
- Homework: review the key idea behind States of Matter before you start a problem set.
- Exam revision: use the quick check to test whether you can recall States of Matter without notes.
- Visual learning: play with the interactive lab to see how States of Matter changes when you adjust its inputs.
- Teaching a friend: explain States of Matter in your own words, then compare your version with the key ideas.
Chemistry explains medicine, food, cleaning products, fuels and building materials.
Frequently asked questions
What is States of Matter?
Solids, liquids and gases differ in how particles are arranged and move.
What will I learn in States of Matter?
Solids keep shape and volume. Liquids flow but keep volume. Gases fill any container.
Is States of Matter part of Chemistry?
Yes. It is one of 150 Chemistry topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the States of Matter lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study States of Matter?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.