Science · Grades 6–9
Particle models of matter · revision card
A particle model explains observations; it is not a literal photograph of individual particles.
Keep these ideas clear
Separate scale levels
A particle model explains observations; it is not a literal photograph of individual particles.
Conservation
In a sealed system, a physical change does not remove matter from the system.
Two useful examples
A gas is compressed more easily than a liquid. Which particle-model feature helps explain this?
Gas particles have much more space between them.
Gas particles have much more space between them.
During melting, which statement best describes a simple particle model?
Particles become less fixed in their arrangement.
Particles become less fixed in their arrangement.
Explain it without looking
- State one limitation of a simple drawing of circles used to model a liquid.
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Learning preview · teacher review required. Grade bands are approximate, not official curriculum alignment.