Particle model presentation
- 2. In our world, matter exists in three states: Solid Liquid Gas
- 3. Solid o Strong forces hold the particles together o The particles only move a little o They do not change position, but vibrate to and fro in one position
- 4. Liquid o The forces that hold the particles together are weaker than in solids o The particles can change position by sliding over each other
- 5. Gas o The forces holding the particles are very small o The particles can travel in all direction
- 6. Changes in Temperature Solid Condensation Liquid Gas Evaporation
- 7. Changes in Solids When a solid is heated, it expands and when it cools it contracts. E.G Railways: There are gaps between the end of the rails. In hot weather, the rail will expand and will buckle up.
- 8. Changes in Liquids When liquids are heated, they expand much more than solids for a given temperature. E.G When water get hot, it expands and rises up the glass tube. While when the water is cool, the level of the water in tube falls
- 9. Strange fact about water! When water cooled, it expands again when it’s temperature drops below 4 degree celcius. After 4 degree celcius, it will start to expand until it reaches 0 degree celcius.
- 10. Changes in Gas o Gases expand when they are heated o Contract when they are cooled E.G. Hot air balloons: When the air in the balloon is heated, it expands and fills the balloon. The density of the air falls and it becomes less dense than the air around it. The surrounding area exerts an upthrust force which is greater than the weight on it.
- 11. Thank You For Paying Attention !!!