7TH GRADE · STRUCTURE OF MATTER
Interaction between particles and states of matter
Attraction, repulsion and differences between solids, liquids and gases.
The entire theory of the lesson is collected here; you can read it without an account. In interactive mode, the same theory appears as cards, followed by questions. with checking the answer and task, and progress is saved.
Basic Concepts
Interaction of molecules
At short distances, particles of matter simultaneously exhibit attraction and resistance to excessive proximity.
Attraction holds the parts of the body together, and a sharp increase in repulsion prevents the solid body from being compressed to zero volume.
Solid state
A state of matter in which particles vibrate around stable positions and the body retains its shape and volume.
A crystal resists changing shape because its particles are more connected and ordered than in a liquid.
Liquid and gas
A liquid retains volume, but takes the shape of a container, while a gas retains neither its own shape nor volume.
Liquid particles remain close and change neighbors, while gas particles are removed and freely fill the entire accessible vessel.
Physical quantities
Volume of substance
The region of space occupied by a given amount of matter.
Unit: cubic meter ·
Tasks on the topic
Statements, answer options and the walkthrough.