1. Chapter 4

2. Scientist of the Day

3. Joseph Louis Gay-Lussac Father arrested in the French Revolution so he was raised by an abbot Used hot air balloons to find gas laws, gave credit to Charles Found 2 new elements Figured out formula for water Married an unimportant shop girl because he saw her reading a chemistry book

4. States of Matter January 4, 2016 6 th grade Chapter 4.1

5. States of Matter Which ones do you remember?

6. Most Common States of Matter Solid: Definite shape, definite volume Liquid: Indefinite shape, definite volume Gas: Indefinite shape, indefinite volume (depends on pressure) There are other states of matter like plasma, superfluid, strange matter, etc but they’re rare outside of a lab

7. States of Matter

8. Solids All matter is made of molecules, and molecules are always moving Molecules in solids are close together and don’t move much: more like shaking This lets the solid stay in the shape you put it in Shape can be crystalline or amorphous Crystalline: regular, repeating pattern, melts at 1 temp Amorphous: random or imperfect pattern, melts over a range of temperatures

9. Examples CrystallineAmorphous

10. Liquids Molecules in liquids are close together, but they move around a lot Liquids fill the bottom of their container as much as possible Things like surface tension and viscosity or cohesion might change how long it takes to do that Some things that seem like solids behave like liquids if you leave them long enough o Dough o Pitch drop experiment

11. Properties of Liquids Fluid: another word for a liquid. A substance that flows. Surface tension: inward force/pull of molecules in a liquid trying to give it the smallest surface area Sphere is the best volume : surface area, so high surface tension = closer to sphere shape Viscosity: how well a liquid resists flowing. If it’s sticky, it’s viscous/high viscosity. If it’s easy to pour, it’s not viscous/low viscosity

12. Which property is being shown?

13. Gases Molecules in a gas spread out as much as possible – they fill the entire container Gas molecules move a lot compared to liquids or solids Want to know the volume, pressure, and temperature of a gas – changing one of these will change the other two

14. Review TemperatureVolume

15. Pressure Since gas molecules fill the entire container and are constantly moving, they are constantly banging into the sides of their container This is called pressure Pressure can be used for liquids & solids, but then you have to worry about gravity too

16. Changes of State January 5, 2016 6 th grade Chapter 4.2

17. Most Common States of Matter Solid: Definite shape, definite volume Liquid: Indefinite shape, definite volume Gas: Indefinite shape, indefinite volume (depends on pressure) There are other states of matter like plasma, superfluid, strange matter, etc but they’re rare outside of a lab

18. States of Matter

19. Pressure Since gas molecules fill the entire container and are constantly moving, they are constantly banging into the sides of their container This is called pressure Pressure can be used for liquids & solids, but then you have to worry about gravity too

20. Changes of State Which ones do you remember?

21. Melting Melting: solid  liquid, getting warmer In pure, crystalline substances, melting occurs at only 1 temperature: the melting point. Different substances have different melting points o Water 0°C o Salt (NaCl) 801°C Solid’s molecules were already vibrating: now they vibrate so fast that they break free from other molecules and can float around Add thermal energy to melt something

22. Freezing Freezing: liquid  solid, getting colder Opposite of melting You can use melting point and freezing point interchangeably because they happen at the same temperature

23. Vaporization Vaporization: liquid  gas Can be caused by evaporation or boiling Add thermal energy Evaporation: liquid  gas, below the boiling point Only some liquid molecules have enough energy to escape their bonds to other liquid molecules No boiling Boiling: liquid  gas, getting hotter Happens at the boiling point Bubbles of gas form at & below the surface

24. Condensation Condensation: gas  liquid, getting colder Losing thermal energy The gas molecules don’t have enough energy to be bouncing around, so they become liquid and stick closer together Dew forming Making clouds

25. Most Common Path

26. Sublimation Sublimation: solid  gas Sometimes you can go straight from a solid to a gas Dry ice (carbon dioxide, CO 2 )

27. Graphing Changes of State

28. How does this work?

29. Gas Behavior, part 1 January 12, 2016 6 th grade Chapter 4.3

30. How does a hot air balloon work?

31. Gas Molecules What will happen if we increase the temperature of a gas? Temperature: the energy of molecules moving

32. Increasing Temperature If the temperature goes up, the gas molecules move faster If the molecules are moving faster, they’ll hit the sides more often This increases pressure If you want to keep pressure the same, you have to increase volume instead

33. Charles’ Law Temperature goes up, volume goes up Temperature and volume are directly proportional T ∝ V

34. Graphing Charles’ Law Temperature (K) Temperature (°C) Volume (mL) 050 2054 4058 6062 8066 10070 12074

35. Graphing Charles’ Law Charles’ law is a case where we have to use K If we graphed with °C instead of K, we wouldn’t be directly proportional Sometimes we’d have a negative temperature with a positive volume – that’s not directly proportional Kelvin can never be negative, so it fixes the problem!

36. Pressure Since gas molecules fill the entire container and are constantly moving, they are constantly banging into the sides of their container This is called pressure Pressure can be used for liquids & solids, but then you have to worry about gravity too

37. Increasing Pressure

38. Boyle’s Law Boyle’s Law looks at volume and pressure Volume and pressure are inversely proportional Inversely proportional: when one goes up, the other goes down

39. Graphing Boyle’s Law Volume (mL)Pressure (kPa) 30020 25024 20030 15040 10060 50120

40. Graphing Boyle’s Law Shows up as a curve Any time we multiply volume x pressure for the same amount of gas, we’ll get the same number

41. Vaporization Vaporization: liquid  gas Can be caused by evaporation or boiling Add thermal energy Evaporation: liquid  gas, below the boiling point Only some liquid molecules have enough energy to escape their bonds to other liquid molecules No boiling Boiling: liquid  gas, getting hotter Happens at the boiling point Bubbles of gas form at & below the surface

42. Graphing Changes of State