Liquid — Science definition
A state of matter with a fixed volume but no fixed shape; particles are close but can flow past each other.
Where it is taught
- States of Matter & Phase Changes — Phases of Matter, Physical Science: Matter, Forces & Energy, Grade 8
In use
Many everyday materials are described using three familiar states — solid, liquid, or gas — and the real difference between them comes down to how the tiny particles inside are arranged and how fast they're moving.
States of Matter & Phase Changes
Questions using liquid
Problem 1
While a pure liquid boils at fixed pressure, what happens to its temperature during the phase change?
- It stays the same until all the liquid has boiled away
- It rises steadily
- It drops suddenly
- It becomes negative
Answer and explanation
It stays the same until all the liquid has boiled away
At fixed pressure, added energy changes particle interactions during boiling rather than raising temperature while liquid and vapor coexist.
Problem 2
Which phase change describes water vapor turning into liquid water on a cold glass?
- Melting
- Evaporation
- Condensation
- Sublimation
Answer and explanation
Condensation
Gas turning into liquid is condensation.
Problem 3
A heating curve shows a solid's temperature rising, then flattening out at 0°C while it melts, then rising again as a liquid. What temperature does that flat section occur at?
Answer and explanation
0 °C
The flat section on a heating curve occurs at the melting point, given here as 0°C.
Problem 4
Dry ice (solid carbon dioxide) turning directly into a gas without becoming a liquid is an example of…
- melting
- sublimation
- condensation
- freezing
Answer and explanation
sublimation
Sublimation is the direct change from solid to gas.