1. 1 GCSE Physics Solids, liquids and gases

2. 2 Lesson 4 – The structure of matter Aims: To understand that a substance can change state from solid to liquid by the process of melting To understand that a substance can change state from liquid to gas by the process of evaporation or boiling To recall that particles in a liquid have a random motion within a close-packed structure To recall that particles in a solid vibrate about fixed positions within a close-packed regular structure

3. 3 What are the three states of matter? solid liquidgas

4. 4 Solids Definite shape, Definite volume, Particles close together, fixed, Particles move relatively slowly.

5. 5

6. 6 Liquids No definite shape, definite volume, Take the shape of container, Particles are close together, but mobile Particles move a little quicker.

7. 7 Mercury Mercury is the only metallic element that is a liquid at room temperature. It is more than 13 times heavier than water.

8. 8 Gases No definite shape No definite volume Take the shape and volume of container Particles are far apart Particles move fast

9. 9

10. 10 Comparing states Definite volume Definite Shape CompressibleTemperature increase Solid Liquid Gas

11. 11 Comparing states Definite volume Definite Shape CompressibleTemperature increase SolidYes LiquidYes GasNo

12. 12 Comparing states Definite volume Definite Shape CompressibleTemperature increase SolidYes LiquidYesNo GasNo

13. 13 Comparing states Definite volume Definite Shape CompressibleTemperature increase SolidYes No LiquidYesNo GasNo Yes

14. 14 Comparing states Definite volume Definite Shape CompressibleTemperature increase SolidYes NoSmall Expansion LiquidYesNo Small Expansion GasNo YesLarge expansion

15. 15 solid particles… - are very close together in a fixed arrangement - have a small amount of energy - vibrate but do not move liquid particles… - are close together but have no fixed arrangement - have more energy than solid particles - vibrate and can move about gas particles… - are far apart and have no fixed arrangement - have a large amount of energy - move rapidly in all directions

16. 16 Changing state

17. 17 Changing states of matter Solids can turn into liquids, and liquids can turn into gasses and back again - depending on the temperature. So, we can use the effect of heat on states of matter to measure the temperature of something. COLDWARMHOT

18. Solid Liquid Gas Melt Boil Condense Freeze

19. 19 Changing state is a physical change.

20. Liquid Sublimation Melting Vaporization Condensation Solid Freezing Gas

21. 21 Sublimation Sublimation is the physical changing of a solid into a gas. Only a very few substances change from a solid to a gas without becoming a liquid. Carbon dioxide is an example of a compound that sublimes.

22. 22 Changing state graphs

23. Water and Ice Ice Water and Steam Steam -20 0 20 40 60 80 100 120 0 40120 220760800 Heating Curve for Water Time in seconds Temperature (degrees Celsius)

24. 24 Energy is transferred when something changes state.

25. Water and Ice Ice Water and Steam Steam -20 0 20 40 60 80 100 120 0 40120 220760800 Heating Curve for Water Time in seconds Temperature (degrees Celsius)

26. 26 Liquid to a gas At its boiling point water changes state from a liquid into a gas. Energy must be transferred to the water so that it’s molecules can change from a liquid to a gas.

27. Water and Ice Ice Water and Steam Steam -20 0 20 40 60 80 100 120 0 40120 220760800 Heating Curve for Water Time in seconds Temperature (degrees Celsius)

28. 28 Ice to water When an ice cube at zero Celsius is left on a table on a warm day it will melt. Energy from the room is transferred to the ice cube to change it from a solid to a liquid. When all of the ice has melted the water will start to increase in temperature towards that of the room.

29. 29 Water to ice Place water into an ice cube tray and then place it into a freezer. The water in the tray is hotter than the freezer. As energy is transferred from the water to the freezer the temperature drops. At zero degrees Celsius the water keeps transferring energy to the freezer but does not get colder. Instead the water changes state from a liquid to a solid. When all of the water has turned to ice it will again start to fall in temperature until it has the same temperature as the freezer compartment.

30. 30 Two states at the same temperature

31. Water and Ice Ice Water and Steam Steam -20 0 20 40 60 80 100 120 0 40120 220760800 Heating Curve for Water Both Water and Steam Time in seconds Temperature (degrees Celsius)

32. 32 At 100 degrees Celsius water and steam can both occur

33. Water and Ice Ice Water and Steam Steam -20 0 20 40 60 80 100 120 0 40120 220760800 Heating Curve for Water Ice and Water Time in seconds Temperature (degrees Celsius)

34. 34 At zero degrees Celsius both ice and water can both occur.

35. Water and Ice Ice Water and Steam Steam -20 0 20 40 60 80 100 120 0 40120 220760800 Heating Curve for Water Time in seconds Temperature (degrees Celsius)

36. 36 Summary – The structure of matter A substance can change state from solid to liquid by the process of melting A substance can change state from liquid to gas by the process of evaporation or boiling Particles in a liquid have a random motion within a close-packed structure Particles in a solid vibrate about fixed positions within a close-packed regular structure

37. 37 The three states of matter are..................,.................. and................... All matter consists of tiny.................. travelling at............. speed.

38. 38 A solid has a definite size and a definite.................. because the forces between its.................. are very................... A liquid has weaker forces between its.................. and so does not have a definite...................

39. 39 If a substance is cooled down, its molecules move at a.................. speed. When some molecules pass through some other molecules, we call it............. The twisting and jerking of smoke particles when they are hit by air.................. is called...................

40. 40 Evaporation and Boiling

41. 41 Evaporation

42. 42 Evaporation Liquid cools because it loses higher energy molecules or atoms Air cools because the molecules leaving give up a lot of energy to break free, so they have much lower energy after they gain their freedom

43. 43 Evaporation from liquids takes place at all temperatures; it occurs when particles at the surface gain enough energy to move away from the attractive forces of neighbouring particles..

44. 44 How to make a liquid evaporate more quickly? Increase the temperature Increase the surface area Reduce the humidity Blow air across the surface

45. 45 Boiling

46. 46 Boiling Molecules break free of the liquid bonds and form little bubbles If the vapor pressure in the bubble is large enough to resist the pressure of the liquid, and the air pressure above the interface they rise and escape to the outside Remember, liquid is cooling and air is cooling

47. 47 Boiling in a liquid only takes place at the boiling point; when a liquid boils, bubbles of vapour form in the body of liquid and rise to the surface, where they collapse and release the vapour into the atmosphere

48. 48 Changing the boiling point Impurities Impurities raise the boiling point of water. Pressure Reduce the pressure lowers the boiling point.

49. 49 Pressure cooker P≈2P 0, boiling point at about 120 ℃

50. 50 rapid,gas bubbles are produced throughout. slow; occurs at the surface. When will these phenomenon occur? What will happen during and after these phenomenon?