1. Changes of State
Unit 6 Matter Lesson 6

2. Moving Particles
I need four students to volunteer.

3. Moving Particles I need four students to volunteer.
Form a square. As a square, these students represent a solid.

4. Moving Particles I need four students to volunteer.
Form a square. As a square, these students represent a solid.
Now move slightly while keeping your feet in place. This mimics the movement of particles in a solid, which vibrate but are fixed in place.

5. Moving Particles I need four students to volunteer.
Form a square. As a square, these students represent a solid.
Now move slightly while keeping your feet in place. This mimics the movement of particles in a solid, which vibrate but are fixed in place.
Now, move around each other while remaining close to each other. This mimics particle movement in a liquid.

6. Moving Particles I need four students to volunteer.
Form a square. As a square, these students represent a solid.
Now move slightly while keeping your feet in place. This mimics the movement of particles in a solid, which vibrate but are fixed in place.
Now, move around each other while remaining close to each other. This mimics particle movement in a liquid.
Now, run freely throughout the classroom. This mimics the movement of particles in a gas.

7. Watery World
Water exists as a solid, liquid, and a gas under normal conditions on Earth’s surface. What properties allow water to exist on Earth in all three states?

8. Watery World
Water exists as a solid, liquid, and a gas under normal conditions on Earth’s surface. What properties allow water to exist on Earth in all three states?
It’s boiling and melting points are both within the range of normal Earth temperatures.

9. Investigating Conservation of Mass
We will do a quick lab to design and carry out a procedure to investigate the conservation of mass.

10. Boiling Water Without Heating It Quick Lab
We will do another quick lab where we will boil water by decreasing atmospheric pressure, and make observations. We will do this to investigate the connection between pressure and boiling point.

11. Change of Pace Virtual Lab
We will now do a virtual lab where we will observe a change and determine whether it was a physical change or not. We will do this to identify physical changes of space.

12. Introduction
Welcome to the lesson, "Changes of State," where you'll learn how particle models can be used to describe how matter changes state.
EQ: What happens when matter changes state?
The vocabulary words for this lesson are freezing, melting, evaporation, boiling, condensation, sublimation, and deposition.

13. Vocabulary Freezing: The change of state from a liquid to a solid
Melting: The change of state from a solid to a liquid
Evaporation: The change of state from a liquid to a gas that usually occurs at the surface of a liquid over a wide range of temperature
Boiling: The change of state from a liquid to a gas that occurs at a specific temperature
Condensation: The change of state from a gas to a liquid
Sublimation: The change of state from a solid directly to a gas
Deposition: The process in which material is laid down

14. Bigger Space, not Bigger Particles
You might think that matter expands because the particles that make up matter become larger. Expansion of matter occurs as matter changes state due to an increase in the space between the particles. The actual size of each particle remains the same.

15. Bigger Space, not Bigger Particles
You might think that matter expands because the particles that make up matter become larger. Expansion of matter occurs as matter changes state due to an increase in the space between the particles. The actual size of each particle remains the same.
Do you think the behavior of the particles in solids, liquids, and gases influences their properties? Why or why not?

16. Bigger Space, not Bigger Particles
You might think that matter expands because the particles that make up matter become larger. Expansion of matter occurs as matter changes state due to an increase in the space between the particles. The actual size of each particle remains the same.
Do you think the behavior of the particles in solids, liquids, and gases influences their properties? Why or why not?
Yes. Solids hold their shape and are often rigid, and the particles in a solid are held tightly together. Liquids flow, and the particles in a liquid slide around each other. Gases rise and the particles spread out and move independently of each other.

17. Particle Motion in Solids
You might think that particles in a solid do not move. Although the particles in a solid stay in more or less a fixed position relative to other particles, all particles in the solid are vibrating essentially in place.

18. Freezing Point
Most students associate the term freezing only with cold temperatures. However, the term actually applies to any change of state from a liquid to solid, regardless of temperature. Freezing can occur at low or high temperatures. For example, ammonia freezes at C, and magnesium freezes at 650 C.

19. Solid Facts
What can happen when a substance gains or loses energy?

20. Solid Facts What can happen when a substance gains or loses energy?
The temperature of the substance can change; if the substance gains or loses enough energy, the substance can undergo a change of state.

21. Solid Facts What can happen when a substance gains or loses energy?
The temperature of the substance can change; if the substance gains or loses enough energy, the substance can undergo a change of state.
When the temperature of a liquid drops, what happens to the particles that make up the liquid?

22. Solid Facts What can happen when a substance gains or loses energy?
The temperature of the substance can change; if the substance gains or loses enough energy, the substance can undergo a change of state.
When the temperature of a liquid drops, what happens to the particles that make up the liquid?
As the temperature drops, particles would have less kinetic energy and slow down.

23. Solid Facts What can happen when a substance gains or loses energy?
The temperature of the substance can change; if the substance gains or loses enough energy, the substance can undergo a change of state.
When the temperature of a liquid drops, what happens to the particles that make up the liquid?
As the temperature drops, particles would have less kinetic energy and slow down.
If the particles slow down enough, what happens?

24. Solid Facts What can happen when a substance gains or loses energy?
The temperature of the substance can change; if the substance gains or loses enough energy, the substance can undergo a change of state.
When the temperature of a liquid drops, what happens to the particles that make up the liquid?
As the temperature drops, particles would have less kinetic energy and slow down.
If the particles slow down enough, what happens?
The attraction between the particles increases and the particles pack together to form a solid.

25. Solid Facts
When the temperature of a liquid drops, what happens to the particles that make up the liquid?
As the temperature drops, particles would have less kinetic energy and slow down.
If the particles slow down enough, what happens?
The attraction between the particles increases and the particles pack together to form a solid.
Gold has a freezing point of 1,064 C. What is gold’s melting point?

26. Solid Facts
When the temperature of a liquid drops, what happens to the particles that make up the liquid?
As the temperature drops, particles would have less kinetic energy and slow down.
If the particles slow down enough, what happens?
The attraction between the particles increases and the particles pack together to form a solid.
Gold has a freezing point of 1,064 C. What is gold’s melting point?
1,064 C.

27. Boiling
Imagine the process of boiling a pot of water. As the water heats up, but before it boils, what change of state is occurring? Why?

28. Boiling
Imagine the process of boiling a pot of water. As the water heats up, but before it boils, what change of state is occurring? Why?
Evaporation, because as the water warms up, water vapor particles are escaping from the surface.

29. Boiling
Imagine the process of boiling a pot of water. As the water heats up, but before it boils, what change of state is occurring? Why?
Evaporation, because as the water warms up, water vapor particles are escaping from the surface.
At first, the water boils slowly, then it boils faster and faster. Is the water getting hotter when it boils faster? Explain.

30. Boiling
Imagine the process of boiling a pot of water. As the water heats up, but before it boils, what change of state is occurring? Why?
Evaporation, because as the water warms up, water vapor particles are escaping from the surface.
At first, the water boils slowly, then it boils faster and faster. Is the water getting hotter when it boils faster? Explain.
No. The water has reached its boiling point of 100 C so the temperature does not change until the change in state is complete or all of the liquid water is changed to water vapor.

31. Changing States
What are the main ideas for the paragraphs on sublimation and deposition?

32. Changing States
What are the main ideas for the paragraphs on sublimation and deposition?
Sublimation: A solid changes directly into a gas.
Deposition: A gas changes directly into a solid.

33. Changing States
What are the main ideas for the paragraphs on sublimation and deposition?
Sublimation: A solid changes directly into a gas.
Deposition: A gas changes directly into a solid.
You might think that when a substance changes from a solid to a gas, it must go through the liquid state first. This does not occur in sublimation or deposition. These changes occur with no liquid state in between.

34. Changing States
You might think that when a substance changes from a solid to a gas, it must go through the liquid state first. This does not occur in sublimation or deposition. These changes occur with no liquid state in between.
Sublimation may seem like an unusual process, but it has proved very useful in the production of some items. Have you ever eaten freeze- dried food? Freeze-dried food is very lightweight and can be stored for long periods of time. To create freeze-dried food, the food is first frozen; then the surround pressure is lowered. Finally, the temperature is increased insufficiently to force the frozen water in the food to sublime directly from solid to gas.

35. Changing States
Sublimation may seem like an unusual process, but it has proved very useful in the production of some items. Have you ever eaten freeze- dried food? Freeze-dried food is very lightweight and can be stored for long periods of time. To create freeze-dried food, the food is first frozen; then the surround pressure is lowered. Finally, the temperature is increased insufficiently to force the frozen water in the food to sublime directly from solid to gas.
What is the name of the process by which a substance changes state from a gas directly to a solid?

36. Changing States
Sublimation may seem like an unusual process, but it has proved very useful in the production of some items. Have you ever eaten freeze- dried food? Freeze-dried food is very lightweight and can be stored for long periods of time. To create freeze-dried food, the food is first frozen; then the surround pressure is lowered. Finally, the temperature is increased insufficiently to force the frozen water in the food to sublime directly from solid to gas.
What is the name of the process by which a substance changes state from a gas directly to a solid?
Deposition

37. Changing States
What is the name of the process by which a substance changes state from a gas directly to a solid?
Deposition
What does it mean when a substance sublimes?

38. Changing States
What is the name of the process by which a substance changes state from a gas directly to a solid?
Deposition
What does it mean when a substance sublimes?
When a substance sublimes, it changes directly into a gas from a solid and does not go through a liquid state.

39. Changing States
What is the name of the process by which a substance changes state from a gas directly to a solid?
Deposition
What does it mean when a substance sublimes?
When a substance sublimes, it changes directly into a gas from a solid and does not go through a liquid state.
Why doesn’t the mass of a substance change when it changes from one state of matter to another?

40. Changing States
What is the name of the process by which a substance changes state from a gas directly to a solid?
Deposition
What does it mean when a substance sublimes?
When a substance sublimes, it changes directly into a gas from a solid and does not go through a liquid state.
Why doesn’t the mass of a substance change when it changes from one state of matter to another?
The mass doesn’t change because the size and number of particles do not change. Only the movement of the particles and the distance between them change.

41. Summary
When a substance gains energy from the environment, the kinetic energy of its particles increases and can overcome the attractions between particles.
Melting changes a solid to a liquid. Evaporation and boiling change a liquid to a gas. Sublimation changes a solid directly to a gas. A substance can lose energy to the environment.
If particles lose enough energy, their kinetic energy can no longer overcome the attraction between particles. Then substances can condense or freeze. Condensation is when a gas changes to a liquid. Freezing happens when a liquid changes to a solid.
Deposition changes a gas directly to a solid.

42. Summary
The melting point is the temperature at which a solid becomes a liquid. The boiling point is the temperature at which a liquid becomes a gas. Substances have characteristic melting points and boiling points. For water at sea level, the melting point is zero degrees Celsius, and the boiling point is 100 degrees Celsius.
When a solid gains enough energy, its particles move apart and the substance begins to melt. This happens at its melting point.
If the liquid loses enough energy, its particles move together and make a solid. This happens at its freezing point. The melting and freezing points of a substance are the same. This is why water melts at zero degrees Celsius as it gains energy and freezes at zero degrees Celsius as it loses energy.

43. Tonight’s Homework
For homework tonight, you will make a concept map about the conservation of mass. Include details about what changes and what does not change when a change of state occurs.