Mr. Leach Mr. Leach

77thth Grade Science Grade Science

What is the kinetic theory of What is the kinetic theory of matter?matter?

•The word kinetic means “motion The word kinetic means “motion or movement”.or movement”.

•This states that atoms and This states that atoms and molecules that make up matter molecules that make up matter are constantly moving and are constantly moving and vibrating in motion.vibrating in motion.

States of MatterStates of Matter

•SolidSolid

•LiquidLiquid

•GasGas

•PlasmaPlasma

When one form of matter is changed in to another form, it is called a phase change.

Solid- How are the molecules Solid- How are the molecules arranged and move?arranged and move?

• They are arranged They are arranged in a fixed position. in a fixed position. They do not They do not change positions.change positions.

• Geometric pattern Geometric pattern called crystals.called crystals.

• Vibrate back and Vibrate back and forth and don’t forth and don’t change position. change position.

Solids- Do they have a definite Solids- Do they have a definite shape or volume?shape or volume?

•Solids have both a definite Solids have both a definite shape and volume.shape and volume.

•You can find the volume of You can find the volume of the solid and see its shape.the solid and see its shape.

Liquids- How are the molecules Liquids- How are the molecules arranged? How do they move?arranged? How do they move?

• Close togetherClose together

• Free to change positionFree to change position

• Vibrate over and around each otherVibrate over and around each other

• The molecules have more energy The molecules have more energy (heat) than a solid.(heat) than a solid.

Liquid- Do they have a definite Liquid- Do they have a definite shape or volume?shape or volume?

• They have no definite shape. They They have no definite shape. They take the shape of the container they take the shape of the container they are placed in.are placed in.

• They do have a definite volume. You They do have a definite volume. You can find the volume of a liquid.can find the volume of a liquid.

Gas- How do the molecules Gas- How do the molecules move and how are they move and how are they arranged?arranged?• Very little attractive force.Very little attractive force.

• They can move freely and They can move freely and independently.independently.

• They want to separate from each They want to separate from each other.other.

• The particles have even more energy The particles have even more energy than that of a liquid and solid.than that of a liquid and solid.

Gases- Do they have a definite Gases- Do they have a definite shape or volume?shape or volume?

• No definite shapeNo definite shape

• No definite volumeNo definite volume

• Therefore, they will fill the container Therefore, they will fill the container regardless of the shape and size. regardless of the shape and size.

• This is because they have very little This is because they have very little attractive force towards each other.attractive force towards each other.

What is plasma?What is plasma?

• Gas-like mixture Gas-like mixture of positively and of positively and negatively negatively charged particles charged particles that exist at that exist at extremely high extremely high temperatures.temperatures.

• Example: Example: lightning boltlightning bolt

SOLID LIQUID GAS

PHASE CHANGES

MELTING EVAPORATION

FREEZING CONDENSATION

ENERGY GAIN

SUBLIMATION

ENERGY LOSS

Phase changes happen Phase changes happen when…when…

• Thermal Energy (heat) is added or Thermal Energy (heat) is added or taken away.taken away.

oror

• When pressure is increased or When pressure is increased or decreased.decreased.

PressurePressure

• Increasing pressure forces atoms or Increasing pressure forces atoms or molecules closer together.molecules closer together.

• Decreasing pressure allows atoms or Decreasing pressure allows atoms or molecules to separate.molecules to separate.

Thermal EnergyThermal Energy

• Adding thermal energy causes atoms Adding thermal energy causes atoms to move faster, creating more to move faster, creating more separation.separation.

• Removing thermal energy (cooling) Removing thermal energy (cooling) causes atoms to move slower and causes atoms to move slower and come closer together.come closer together.