Solids, liquids and gases
The Earth, its atmosphere and the oceans are made from substances in different states. The The scientific theory used to explain the properties of solids, liquids and gases. It involves the arrangement and movement of the particles in a substance. describes the arrangement, movement and The capacity of a system to do work or the quantity required for mechanical work to take place. Measured in joules (J). For example, a man transfers 100 J of energy when moving a wheelbarrow. of A general term for a small piece of matter. For example, protons, neutrons, electrons, atoms, ions or molecules. in a substance. The model explains the A description of the appearance of a substance or how it acts without involving chemical reactions. For example, state, melting point, conductivity, etc. of substances in the solid, liquid and gas state.
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Particle arrangement and movement
The particles in the diagrams could be The smallest part of an element that can exist., A collection of two or more atoms held together by chemical bonds. or Electrically charged particle, formed when an atom or molecule gains or loses electrons., depending on the type of substance.
Explaining physical properties
Solids:
- have a fixed shape and cannot flow, because their particles cannot move from place to place
- cannot be Made smaller by squeezing together., because their particles are close together and have no space to move into
Liquids
- flow and take the shape of their container, because their particles can move around each other
- cannot be compressed, because their particles are close together and have no space to move into
Gases:
- flow and completely fill their container, because their particles can move quickly in all directions
- can be compressed, because their particles are far apart and have space to move into
Question
Use the particle model to explain why an iceberg has a fixed shape.
An iceberg is in the solid state. It has a fixed shape because the particles (water molecules) are arranged in fixed positions.
Question
Use the particle model to explain why water from a river can change shape when filling a container.
Water is in the liquid state. It can flow because its particles can change position and slide past each other.
Question
Use the particle model to explain why air can fill a room.
Air is in the gas state. It fills a room because the particles are far apart and are free to move position.