Matter and Thermal Energy Section 1

Essential Questions

What is the kinetic theory of matter?

How do particles move in the different states of matter?

How do particles behave at the boiling and melting points?

Review Vocabulary

kinetic energy: energy of motion

New Vocabulary

kinetic theory

melting point plasma

heat of fusion

sublimation

thermal expansion

boiling point

heat of vaporization

Kinetic Theory The kinetic theory, also known as kinetic molecular theory, is an explanation of how the particles in gases behave. To explain the behavior of particles, it is necessary to make some basic assumptions. The assumptions of the kinetic theory are as follows:

1. All matter is composed of tiny particles (atoms, molecules, and ions).

2. These particles are in constant, random motion. 3. The particles collide with each other and with the

walls of any container in which they are held. 4. The amount of energy that the particles lose from

these collisions is negligible.

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Changes of State The particles that make up the water are moving fast and colliding with the particles that make up the ice cube. Those collisions transfer energy from the water to the ice. The particles at the surface of the ice cube vibrate faster, transferring energy to other particles in the ice cube.

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What is Matter?

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• Matter is anything that has mass and takes up space.

What do we know about matter?

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SolidsLiquids

GasesPlasma

Solids

• Solids have definite shape and definite volume.

• Solids have mass.• Solids take up space.

Read more!

Particles in Solids:

• Are packed tightly together

• Have very little energy

• Vibrate in place

Liquids

• Liquids take the shape of their container and have definite volume.

• Liquids have mass.• Liquids take up space.

Read more!

Particles in Liquids:

• Are loosely packed

• Have medium energy levels

• Particles flow around each other

Gases

• Gases spread out to fill the entire space given and do not have definite volume.

• Gases have mass.• Gases take up

space.Read more!

Particles in Gases:

• Move freely

• Have LOTS of energy

Plasma State So far, you have learned about the three familiar states of matter—solids, liquids, and gases. However, there is a state of matter beyond the gas state. Plasma is matter that has enough energy to overcome not just the attractive forces between its particles but also the attractive forces within its atoms. The atoms that make up a plasma collide with such force that the electrons are completely stripped off the atoms.

You may be surprised to learn that most of the ordinary matter in the universe is in the plasma state. Every star that you can see in the sky, including the Sun, is composed of matter in the plasma state. Most of the matter between the stars and galaxies is also in the plasma state. The familiar states of matter—solid, liquid, and gas—are extremely rare in the universe.

Plasma

• Lightning is a plasma.• Used in fluorescent light

bulbs and Neon lights.• Plasma is a lot like a

gas, but the particles are electrically charged.

Read more!

Particles in Plasma:

• Are electrically charged

• Have EXTREMELY high energy levels

Thermal Expansion

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Recall that particles move faster and farther apart 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. Substances also contract when they cool.

Solid or Liquid? Some solids are like butter. Instead of having a specific melting point, they soften and gradually turn into a liquid over a temperature range. These solids lack a crystalline structure and are called amorphous solids. One common amorphous solid is glass, shown at the right.

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Solid or Liquid? Liquid crystals form another group of materials that do not change states in the usual manner. Normally, the ordered geometric arrangement of a solid is lost when the substance goes from the solid state to the liquid state. Liquid crystals start to flow during the melting phase, similar to a liquid. But they do not lose their ordered arrangement completely, as most substances do. Liquid crystals will retain their geometric order in specific directions. Many small computing devices and electronics, such as MP3 players, cell phones, TVs, and netbooks, utilize liquid crystal displays (LCDs).

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STATES of matter?

What would it take for matter to move from one state to another?

Energy determines the state!

Add or Subtract Energy. . .

When energy is added, particles move faster!

When energy is taken away, particles move slower!

What will happen? Why?

Solid + Energy = ?

• When energy is added to solids, they become liquids!

• Examples?

Liquid + Energy = ?

• When energy is added to liquids, they become gases!

• What examples can you think of?

Changing States

• There are several names for matter changing states:

–State change

–Phase change

–Physical change

heat of fusion D

melting point C

boiling point B

absolute zero A

At what temperature is the pressure of the vapor in a liquid equal to the external pressure on that liquid?

Assessment

1.

CORRECT

plasmaD

liquidC

gasB

solid A

What is the most common state of matter in the universe?

Assessment

2.

CORRECT

absolute zero D

heat of vaporization C

temperature B

heat of fusion A

What is the amount of energy needed to change a solid to a liquid at its melting point?

Assessment

3.

CORRECT

Properties of Fluids Section 2

Essential Questions

What is Archimedes’ principle?

What is Pascal’s principle?

What is Bernoulli’s principle?

What are some applications of Archimedes’, Pascal’s, and Bernoulli’s principles?

Review Vocabulary

density: mass per unit volume of a material

New Vocabulary

buoyancy

pressure

viscosity

Archimedes’ Principle and Buoyancy In the third century b.c., a Greek mathematician named Archimedes 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. For example, 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.

Buoyancy is the ability of a fluid—a liquid or a gas—to exert an upward force on an object immersed in it.

Pascal’s Principle and Pressure The idea that pressure is transferred through a fluid can be written as an equation: pressure in = pressure out. Since pressure is force over area, Pascal’s principle can be written another way.

Right now, pressure from the air is pushing on you from all sides like the pressure you feel underwater in a swimming pool. Pressure is force exerted per unit area.

Bernoulli’s Principle Daniel Bernoulli (1700–1782) was a Swiss scientist who studied the properties of moving fluids, such as water and air. Bernoulli found that fluid velocity increases when the flow of the fluid is restricted. Placing your thumb over a running garden hose, as shown the figure below, demonstrates this effect. When the opening of the hose is decreased in size, the water flows out more quickly.

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Viscosity Viscosity is the resistance of a fluid to flowing. For example, when you take syrup out of the refrigerator and pour it, as shown below, the flow of syrup is slow. But if this syrup were heated, it would flow much faster. Water flows easily because it has low viscosity. Cold syrup flows slowly because it has high viscosity.

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kilograms D

newtonsC

kilopascals B

gramA

Which is a unit of pressure?

Assessment

1.

CORRECT

gravitational force D

buoyant force C

density B

pressure A

What force does the upward arrow in the diagram at the right represent?

Assessment

2.

CORRECT

changes of state D

hydraulic lift C

buoyancy B

aerodynamics A

Which uses Pascal’s principle?

Assessment

3.

CORRECT

Behavior of Gases Section 3

Essential Questions

How does a gas exert pressure on its container?

How is a gas affected when pressure, temperature, or volume change?

Review Vocabulary

temperature: a measure of the average kinetic energy of all the particles in an object

New Vocabulary

Boyle’s law

Charles’s law

Gases

KINETIC MOLECULAR THEORY OF GASES

1. Gases always move in straight lines and in constant motion2. Gases are widely spaced3. Gases collide with each other and with their container walls without loss of kinetic energy4. Gases behave as individual particles, attraction between them is negligible5. The actual volumes of gases areinsignificant compared to the space they previously occupy

Gas Laws

Mathematical statements of the propertiesand behavior of gases

PROPERTIES OF GASES

1. Gases may be compressed2. Gases expand when less pressure is applied.3. Gases can be mixed4. Gases exert a constant pressure on its container walls.5. Gases have low densities.

Origin of pressure

Boyle’s Law–Volume and Pressure According to Boyle’s law, if you decrease the volume of a container of gas and hold the temperature constant, the pressure from the gas will increase. An increase in the volume of the container causes the pressure to drop, if the temperature remains constant.

Charles’s Law—Temperature and Volume If you’ve watched a hot-air balloon being inflated, you know that gases expand when they are heated. Jacques Charles (1746– 1823), a French scientist, also noticed this. According to Charles’s law, the volume of a gas increases with increasing temperature, as long as the pressure on the gas does not change. As with Boyle’s law, the reverse is also true. The volume of a gas shrinks with decreasing temperature, as shown at the right.

Combined Gas LawBoyle’s Law= At constant temperature, the volume of a gas is inversely proportional to its pressure - VP = K

Charles’ Law= At constant pressure the volume of a gas is directly proportional to its absolute temperature - V/T = K

For a given amount of the gas, any change in the condition of one of the variables will also cause a change in the other two variables in accordance to Boyle’s Law and Charles’ law. For this reason we can combine the 2 gas laws into one mathematical equation called combined gas law.• VP/T = K

V= Volume, P= Pressure, T = Temperature, K= Constant

snowboard D

piston C

skateboard B

hose-end sprayer A

Which uses Bernoulli’s principle?

Assessment

1.

CORRECT