Cambridge Primary Stage 5 Science Notes – Materials and their Structure
Chemistry - Materials and their Structure
1-Stage-5-science-chemistry-notes-materials-and-their-structure
🔬 Materials and Their Structure
5Cm.01 – Using the Particle Model to Describe Solids, Liquids, and Gases
The particle model helps us understand what materials are like by imagining that all substances are made of tiny particles. These particles are too small to see, but their arrangement and movement explain how materials behave.
Table: Comparing Solids, Liquids and Gases
State of Matter | Particle Arrangement | Particle Movement | Key Properties |
Solid | Very close, fixed pattern | Vibrate in place | Fixed shape; fixed volume |
Liquid | Close, random arrangement | Slide past each other | No fixed shape; fixed volume |
Gas | Far apart, random | Move fast in all directions | No fixed shape; no fixed volume; easily compressed |
5Cm.02 – Substances That Are Gaseous & Common Gases at Room Temperature
Not all materials are solids or liquids at room temperature—some are gases.
A gas is a state of matter where particles are far apart and moving fast.
🌬️ Common Gases at Room Temperature
These gases are important in everyday life:
1. Oxygen (O₂)
Makes up about 21% of the air
Needed for breathing and burning (combustion)
2. Nitrogen (N₂)
Makes up about 78% of the air
Does not easily react
Helps keep the air stable
3. Carbon Dioxide (CO₂)
Produced when animals breathe out
Used by plants in photosynthesis
Found in fizzy drinks
4. Water Vapour (H₂O gas)
Water as a gas, formed by evaporation or boiling
Amount varies depending on humidity
Invisible (mist/steam is not water vapour—it’s tiny liquid droplets)
5. Hydrogen (H₂)
A very light gas
Can be used as a fuel
Rare in the atmosphere but common in the universe
Table: Common Gases and Their Uses/Importance
Gas | Where It Is Found | Importance/Use |
Oxygen | Air (21%) | Breathing, combustion |
Nitrogen | Air (78%) | Non-reactive; keeps air stable |
Carbon Dioxide | Air (small amount), respiration | Photosynthesis, fizzy drinks |
Water Vapour | Atmosphere, evaporation | Weather, water cycle |
Hydrogen | Rare in air | Fuel; lightest gas |
🌡️ Understanding Substances as Gases
Some substances (like oxygen or hydrogen) are always gases at room temperature.
Others (like water) can be solid, liquid, or gas depending on temperature.
Whether a substance is a solid, liquid, or gas depends on how strongly its particles are held together and how much energy they have