1. Particulate model of matter 2N1

2. Air freshener Predict how fast the smell reaches the – 1 st person – Middle of the classroom – Last student Raise your hand if you smell it!

3. Let’s see how fast it travels Time Distance from the spray

4. Matter is made up of small particles The spray from the air freshener is made up of tiny particles that are able to move around in air. They can travel from one end of the classroom to the other end!

5. Tiny particles that moves randomly in all direction

6. Diffusion occurs We realize that the smell spread across the classroom from the source. Diffusion has taken place.

7. Definition: A process by which particles of matter move from a region of higher concentration to a region of lower concentration

8. Computer demonstration http://www.biosci.ohiou.edu/introbioslab/Bi os170/diffusion/Diffusion.html

9. Who farted? Smell it last Smell it at the same time!

10. Brownian motion

11. Robert Brown observe pollen grains dancing in the water under his microscope! People at that time thought that pollen grains are ‘alive’ and can move by itself in water!

12. The dancing smoke and powder Demonstration Observe how the smoke behaves Observe the ‘dancing’ powder

13. Einstein explanation Each movement of a pollen grain or a dust particle was caused by a collision with a water particle

14. Computer simulation of Brownian motion Pollen grain Water molecules

15. Particulate model of matter To describe all the motions and arrangements of the tiny particles Applies to solid, liquid and gases.

16. Do you know…. The differences between solid, liquid and gases? How would you explain it?

17. What are their differences?

18. solid liquid gas meltingboiling freezing condensation What are the differences?

19. Differences between the states of matter PropertySolidLiquidGases ShapeFixed shapeNo fixed shape, take shape of their containers VolumeFixed volume No fixed volume CompressibilityCannot be compressed Can be compressed

20. Student demonstration A group of volunteers Hand entanglement

21. Gases Particles in the gaseous state: 1.Weakly attracted to one another 2.Far apart 3.Move freely and randomly

22. Liquid Particles in the liquid state: 1.Attracted to one another 2.Packed closed together 3.Move over short distances

23. Solid Particles in the liquid state: 1.Strongly attracted to one another 2.Packed very closed together 3.Arranged in fixed, regular pattern 4.Vibrate at the fixed position

24. Drawing time! You’ll be assigned an object. Identify if the object has any solid, liquid or gaseous parts Draw the arrangements of the particles

25. Conclusion All matter are made up of tiny particles. The arrangements and movements of these particles are different in solid, liquid and gases.

26. True of False? Diffusion occurs when particles from a region of lower concentration to a region of higher concentration?

27. True of False? The dust in the air ‘dance’ around randomly because of air particles hitting it in random motion.

28. True of False? The particles in liquids are in fixed position with regular patterns.

29. True of False? The particles in gases are strongly attracted to each other.

30. True of False? Solids cannot be compressed because the particles are very closely packed

31. Next lesson Talk more about melting, boiling and evaporation! Revision Mid-year (Chapter 16 – 21)