1. Physical Science Chapter 16
Solids, Liquids, Gases, and Plasma 1

2. 16:1 Kinetic Theory States of Matter
An everyday activity such as eating lunch may include solids, liquids, and gases.
Can you identify the states of matter present in the photo shown? 2

3. The kinetic theory explains how particles in matter behave.3

4. 16:1 Kinetic Theory All matter is composed of small particles
The three assumptions of the kinetic theory are as follows:
All matter is composed of small particles
Particles are in constant, random motion.
Particles collide with each other and walls of their containers 4

5. 16:1 Kinetic Theory
Thermal energy—total energy of a material’s particles; causes particles to vibrate in place. 5

6. 16:1 Kinetic Theory
Average kinetic energy—temperature of the substance, or how fast the particles are moving; the lower the temperature, the slower the particle motion.
States of Matter 20 6

7. 16:1
Thermal Energy
Solid state—particles are closely packed together in a specific type of geometric arrangement.
This attraction between the particles gives solids a definite shape and volume. However, the thermal energy in the particles causes them to vibrate in place. 7

8. kinetic—vibrations and movement within and between the particles
16:1 Kinetic Theory
Thermal energy is the total energy of a material’s particles including:
kinetic—vibrations and movement within and between the particles
potential—stored energy.. 8

9. Average Kinetic Energy
16:1
Average Kinetic Energy
In science, temperature means the average kinetic energy of particles in the substance, or how fast the particles are moving.
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On average, molecules of frozen water at 0°C will move slower than molecules of water at 100°C. 9

10. Average Kinetic Energy
16:1
Average Kinetic Energy
Water molecules at 0°C have lower average kinetic energy than the molecules at 100°C.
Molecules will have kinetic energy at all temperatures, including absolute zero.
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11. Solid State
The type of geometric arrangement formed by a solid is important.
Chemical and physical properties of solids often can be attributed to the type of geometric arrangement that the solid forms. 11

12. Liquid State
What happens to a solid when thermal energy or heat is added to it?
Liquid state—a solid begins to liquefy at the melting point as the particles gain enough energy to overcome their ordered arrangement.
Energy required to reach the melting point is called the heat of fusion. 12

13. Liquid State
Liquid particles have more space between them allowing them to flow and take the shape of their container. 13

14. Liquid State
The amount of energy required to change a substance from the solid phase to the liquid phase at its melting point is known as the heat of fusion.
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15. Liquid Flow
Particles in a liquid have more kinetic energy than particles in a solid.
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16. Liquid Flow
This extra kinetic energy allows particles to partially overcome the attractions to other particles. 16

17. Liquid Flow
Thus, the particles can slide past each other, allowing liquids to flow and take the shape of their container. 17

18. Liquid Flow
However, the particles in a liquid have not completely overcome the attractive forces between them
This causes the particles to cling together, giving liquids a definite volume. 18

19. Gas State
Gaseous state—a liquid’s particles have enough energy to escape the attractive forces of the other particles in the liquid.
Gases do not have a fixed volume or shape.
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Therefore, they can spread far apart or contract to fill the container that they are in. 19

20. Gas State
Heat of vaporization is the energy required for a liquid to change to a gas.
At the boiling point, the pressure of the liquid’s vapor is equal to the pressure of the atmosphere and that liquid becomes a gas. 20

21. Gas State
Gas particles spread evenly throughout their container in the process of diffusion.
Heating curve of a liquid—as a solid melts and a liquid vaporizes, the temperature remains constant; the temperature will increase after the attractive forces of the earlier state are overcome. 21

22. Heating Curve of a Liquid
This type of graph is called a heating curve because it shows the temperature change of water as thermal energy, or heat, is added.
Notice the two areas on the graph where the temperature does not change.
At 0°C, ice is melting. 22

23. Heating Curve of a Liquid
The temperature remains constant during melting.
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After the attractive forces are overcome, particles move more freely and their average kinetic energy, or temperature, increases. 23

24. Gas State
Unlike evaporation, boiling occurs throughout a liquid at a specific temperature depending on the pressure on the surface of the liquid.
The boiling point of a liquid is the temperature at which the pressure of the vapor in the liquid is equal to the external pressure acting on the surface of the liquid.
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25. Plasma State
Plasma—state of matter consisting of high-temperature gas with balanced positively and negatively charged particles.
Video 25

26. Plasma State
All of the observed stars including the Sun consist of plasma. Plasma also is found in lightning bolts, neon and fluorescent tubes, and auroras. 26

27. Plasma State
Scientists estimate that about 99% of all matter in the universe is plasma.
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Although this matter contains positive and negative particles, its overall charge is neutral because equal numbers of both charges are present. 27

28. The separation lines in concrete are called expansion joints.
Thermal Expansion
The kinetic theory also explains other characteristics of matter in the world around you.
Have you noticed the seams in a concrete driveway or sidewalk?
The separation lines in concrete are called expansion joints.
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29. Thermal Expansion
When concrete absorbs heat, it expands. Then when it cools, it contracts.
If expansion joints are not used, the concrete will crack when the temperature changes. 30

30. Expansion of Matter
Particles move faster and separate as the temperature rises. This separation of particles results in an expansion of the entire object, known as thermal expansion.
Thermal expansion is an increase in the size of a substance when the temperature is increased. 31

31. Expansion of Matter
The kinetic theory can be used to explain the contraction in objects, too.
When the temperature of an object is lowered, particles slow down.
The attraction between the particles increases and the particles move closer together. The movements of the particles closer together result in an overall shrinking of the object, known as contraction. 32

32. Expansion in Liquids
A common example of expansion in liquids occurs in thermometers.
The addition of energy causes the particles of the liquid in the thermometer to move faster. 33

33. Expansion in Liquids
The particles in the liquid in the narrow thermometer tube start to move farther apart as their motion increases.
The size of a substance will decrease when the temperature decreases. 34

34. Expansion in Liquids
The liquid has to expand only slightly to show a large change on the temperature scale.
Expansion and contraction occur in almost all solids, liquids and gases. 35

35. Expansion in Gases
Hot-air balloons are able to rise due to thermal expansion of air.
The air in the balloon is heated, causing the distance between the particles in the air to increase. 36

36. Expansion in Gases
As the hot-air balloon expands, the number of particles per cubic centimeter decreases. 37

37. Expansion in Gases
This expansion results in a decreased density of the hot air. Because the density of the air in the hot-air balloon is lower than the density of the cooler air outside, the balloon will rise.
Water is an exception to the expansion rule because it expands as it becomes a solid. 38

38. The Strange Behavior of Water
Water molecules are unusual in that they have highly positive and highly negative areas.
These charged regions affect the behavior of water.
As temperature of water drops, the particles move closer together. 39

39. The Strange Behavior of Water
The unlike charges will be attracted to each other and line up so that only positive and negative zones are near each other.
Because the water molecules orient themselves according to charge, empty spaces occur in the structure.
These empty spaces are larger in ice than in liquid water, so water expands when going from a liquid to a solid state. 40

40. Some substances do not react as expected when changing states.
16:1 Thermal Expansion
Some substances do not react as expected when changing states.
Amorphous solids—lack the tightly ordered structure found in crystals.
Do not have definite temperature at which they change from solid to liquid. 41

41. Examples of amorphous solids are glass, plastic.
16:1 Thermal Expansion
Examples of amorphous solids are glass, plastic.
Liquid crystals do not lose their ordered arrangement completely upon melting; used in liquid crystal displays in watches, clocks, calculators and some notebook computers.
End Section 1 42

42. Section 16-2 Properties of Fluids
Buoyancy—ability of a fluid (liquid or gas) to exert an upward force on an object immersed in it. 43

43. Section 16-2 Properties of Fluids
1. An object in a fluid will float if its weight is less than the buoyant force acting on it from the fluid. 44

44. Section 16-2 Properties of Fluids
2. An object in a fluid will sink if its weight is more than the buoyant force acting on it from the fluid. 45

45. Section 16-2 Properties of Fluids
An object will float if its density is less than the density of the fluid it is placed in. 46

46. 16:2 Properties of Fluids
Do you know why ships float? What keeps them from sinking? Some ships weigh tons. How can something that heavy float? The Diamond Princess Ship weighs 113,000 tons, 951 feet long, can carry 3100 passengers and has 15 decks. Imagine the total weight of such a ship. 47

47. 16:2 Properties of Fluids
Boats float because a greater force is pushing up on the ship—an opposing weight. The supporting force is called buoyant force. 48

48. 16:2 Archimedes’ Principle
Archimedes was a Greek mathematician who made a discovery about buoyancy.
Archimedes found that the buoyant force on an object is equal to the weight of the fluid displaced by the object. This is known as Archimedes Principle. 49

49. 16:2 Archimedes’ Principle
If you place a block of wood in water, it will push water out of the way as it begins to sink—but only until the weight of the water displaced equals the block’s weight. When the buoyant force become equal to the weight of the block, it floats. If the weight of the water displaced is less than the weight of the block, the object sinks. 50

50. 16:2 Archimedes’ Principle51

51. 16:2 Archimedes’ Principle
Density.
Would a steel block the same size as the wood float in the water? Why?
The volume of the blocks and the volume of the water displaced each have different masses. If the three equal volumes have different masses, they must have different densities. Remember, density is the mass per unit volume. The density of the steel block is greater than the density of the water. 52

52. 16:2 Archimedes’ Principle
Suppose you could take the same mass of steel but shape in the shape of a ship’s hull. The hull would be filled with air. Now the same mass takes up a larger volume. The overall density of the steel boat and air is less than the density of water. The boat will now float. 53

53. 16:2 Pascal’s Principle Pressure is the force exerted per unit area.
If you are underwater, you feel the pressure of the water. An object will float if its density is less than the density of the fluid it is placed in. Pascal’s principle states that pressure applied to a fluid is transmitted throughout the fluid.
Pressure is the force exerted per unit area.
Example: If you squeeze the bottom of a toothpaste tube, the paste comes out the top. Pascal’s Principle.
Pascal’s Principle 54

54. 16:2 Pascal’s Principle
Hydraulic machines are machine that move very heavy loads using Pascal’s Principle.
In a hydraulic lift, a pipe is filled with fluid and connects small and large cylinders. Pressure is applied to the small cylinder and is transferred through the fluid to the large cylinder. 55

55. 16:2 Pascal’s Principle
Because the pressure remains constant throughout the fluid, more force is available to lift a heavy load by increasing the surface area.
Do the Math 16-2 56

56. 16:2 Bernoulli’s Principle
David Bernoulli was a Swiss scientist who studied the properties of moving fluids such as water and air. He found, as the velocity of a fluid increases, the pressure exerted by the fluid decreases. Airplanes use this principle to fly. 57

57. 16:2 Bernoulli’s Principle
An airplane wing is curved. As the plane moves forward, the air passing over the top of the wing travels faster than the
air passing below it. Thus, the pressure above the wing is less than the pressure below it. This results in a net upward force on the wing. This upward force contributes to the lift of an airplane wing. 58

59. Increased temperature will lower the viscosity.
16:2 Fluid Flow
Another property exhibited by fluid is its tendency to flow.
A resistance to flow by a fluid is called viscosity. Molecular structure determines a fluid’s viscosity.
Fluids vary in their tendency to flow.
Cold syrup doesn’t want to flow as easily as water. The syrup’s viscosity is high because it flows slowly.
Increased temperature will lower the viscosity. 60

60. 16:3 Behavior of Gases
Without gravitational forces, the air we breathe would float off into space. Gases tend to take the shape of the container that holds them. Our atmosphere is held in place by the gravitational force on the tiny gas particles. 61

61. Gravity exerts pressure downward toward the center of the earth.
Pressure is the amount of force exerted per unit of area.
Pressure is measured in units called pascal (Pa).
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62. 16:3 Particle Collisions
Gas particles are constantly moving and colliding with anything in their path. The collisions of particles of gas in the air result in atmospheric pressure. 63

63. Gas Particles colliding produce a pressure.
Moving particles colliding with the inside walls of a container result in gas pressure.

64. Boyle’s Law relates pressure and volume.
16:3 Particle Collisions
Boyle’s Law relates pressure and volume.
Volume decreases as pressure increases.
Pressure decreases as volume increases. 65

65. 16:3 Particle Collisions
Pressure multiplied by volume is always equal to a constant if the temperature is constant. 66

66. 16:3 Particle Collisions
Pressure is the amount of force exerted per unit of area, or P=F/A. (P is pressure, F is force and A is area.) Pressure is measured in pascals (Pa), the SI unit of pressure 67

67. 16:3 Particle Collisions
Because pressure is the amount of force divided by area, one pascal of pressure is one Newton per square meter or 1 N/m2. 68

68. If a substance has mass and energy it will move.
16:3 Particle Collisions
If a substance has mass and energy it will move.
Electrolysis is used to remove the hydrogen and oxygen from water. 69

69. 16:3 Particle Collisions
This is a small pressure unit, so most pressures are given in kilopascals (kPa) or 1,000 pascals. At sea level, atmospheric pressure is kPa. This means that at Earth’s surface the atmosphere exerts a force of about 101,300 N on every square meter—about the weight of a large truck. 70

70. 16:3 Particle Collisions
Often gases are held within containers. Balloons and bicycle tires are considered
containers. They remain inflated because of collisions air particles have with the walls of their containers. 71

71. 16:3 Particle Collisions
If more air is pumped into the balloon or tire, the number of air particles is increased. This causes more collisions with the walls of the container, which causes the container to expand. 72

72. 16:3 Boyle’s Law
Why do you think gases used in industry are kept in pressurized containers?
To reduce the volume they occupy, which makes them easier to transport. 73

73. 16:3 Boyle’s Law
Robert Boyle, a British scientist, found that if you decrease the volume of a container of gas and hold the temperature constant, the pressure of the gas will increase. Pressure decreases as volume increases. Pressure multiplied by volume is always equal to the constant if the temperature is constant. 74

74. 16:3 Boyle’s Law
When Boyle’s law is applied to real life situations, we find that pressure multiplied by the volume is always equal to a constant if the temperature is constant. 75

75. 16:3 Temperature-Pressure Law
On aerosol cans there is a warning “keep away from heat.” Do you know why? 76

76. Charles’ Law relates volume and temperature.
At a constant pressure, volume increases as temperature increases.
At a constant pressure, volume decreases as temperature decreases.
Do The Math 16-3 77

77. Review for Test
Test coming soon.
Homework due. 78