What does the Particle Model of Matter describe?

• A. Matter is made of atoms that are fixed in place
• B. Matter is made of tiny moving particles that attract each other and have spaces between them
• C. Matter is continuous and infinitely divisible
• D. All matter is energy

Answer: (B)

Matter is made of tiny moving particles that attract each other and have spaces between them. This idea means substances aren’t just continuous blobs; they’re built from particles that continually jiggle and move, with empty space separating them. How strongly the particles attract and how fast they move explains why materials feel rigid as solids, flow as liquids, or spread out as gases. In solids, strong attractions keep particles in place with only vibrations. In liquids, a bit weaker attraction lets particles slide past each other. In gases, particles move quickly and are far apart, with mostly empty space between them. Heating gives particles more kinetic energy, increasing motion and spacing, which can cause expansion or a change of state; cooling does the opposite. The other descriptions don’t fit this picture of discrete moving particles with spaces between them.