Physical Science Chapter 3

Bellwork

• Pre-test

States of Matter

• States of Matter: Materials can be classified as solids, liquids, or gases based on whether their shapes and volumes are definite or variable.

Solids

• Solid: a state od matter in which the materials have definite shape and a definite volume.

Solid

Definite*

• Definite: the shape and volume of a material won’t change when you move it• Definite does not mean it will

never change• Almost all solids have a closely

packed atomic arrangement

Solid, Liquid, Gas

Liquids

• Liquid: the state of matter in which a material has a definite volume, but not a definite shape

Liquid

Liquid

• Liquid: takes the shape of the container it is in• It does not change its

volume to fit the container

Liquid

Liquid

Bellwork

•What is the main difference between the different states of matter?

Gases

•Gas: a state of matter in which a material has neither a definite shape nor a definite volume

Read the paragraph about gas

• Gas: more space between atoms• Gas can be compressed into

smaller spaces• Gas spreads out when

released from compaction

Gas

Other states of matter

•Almost all matter on Earth is solid, liquid, or gas.•99 % of the universe matter

at high temperatures is in the form of plasma

Plasma

Plasma

Homework/classwork

• Complete your work/study book pages 25-26 questions 1-10

Create a Comparison Chart

Liquid

GasSolid

Directions• Look back at your notes and

the book and tell whether each state has definite volume, definite shape, variable volume, or variable shape.

Bellwork

•What makes plasma so different from the other states of matter?

Kinetic Theory

•Kinetic energy: is the energy an object has due to its motion (comes from the Greek word “to move”)

Kinetic Theory

• The faster an object moves, the greater the kinetic energy is.• A baseball thrown at 85 mph has

more kinetic energy than one thrown at 75 mph• The kinetic theory suggests that

the materials in the ball are moving too

Kinetic Theory

•Kinetic Theory of Matter: all particles of matter are in constant motion

Behavior of Gases•Like the game of pool

Motion in gases

•At room temperature, the average speed of particles of gas is 1600 kilometers per hour–994 mph!

Motion in Gases

•Not all atoms move at the same speed, but the kinetic energy remains the same

Look on page 72

• Two helium atoms bounce around the jar.• They collide with each other and

the jar.• One may lose speed while the

other gains speed.• The total energy remains the

same!

Attraction ;-)

• There are forces of attraction among the particles in all matter.• The faster the particles are

moving (like in gas) these forces of attraction are not as strong

Kinetic Theory of Gases

• The constant motion of particles in a gas allows a gas to fill a container of any shape or size.

Kinetic Theory of Gases 3 Points

• 1: Particles in a gas are in constant, random motion• 2. The motion of one particle is

unaffected by the motion of the other particles unless the particles collide.• 3. Forces of attraction among particles in

a gas can be ignored under ordinary conditions.

Air Freshener

• We will divide into groups• Groups will go to different corners of the room• I will spray the air freshener in a far corner of

the room and we will see how long it takes for the gas particles to travel to each corner

Behavior of Liquids

•Mass of an element can have an effect on movement•Mercury (which is a liquid at

room temperature) has 50 times the mass of a helium atom

Behavior of a liquid

• The arrangement of the atoms has an effect on movement• The particles of a liquid are much

closer together than particles of a gas–This makes the power of

attraction much greater

Bellwork

•What is the Kinetic Theory of Matter?

Behavior of Liquids

• A liquid takes the shape of its container because particles in a liquid can flow to new locations.• The volume of a liquid is constant

because forces of attraction keep the particles close together

Behavior of Solids

•Compare the activity of solid particles to that of people in a movie theater

Behavior of Solids

• Solids have definite shape and definite volume because particles in a solid vibrate around fixed locations

Quick assessment

• Write at least two paragraphs (5-7 complete sentences each paragraph) explaining how the kinetic theory can be used to explain the general characteristics of solids, liquids, and gases.

• This will be graded as a quiz ;-)

Pressure

•Pressure is the result of a force distributed over an area

Pressure

• Speed affects pressure: the faster something is moving the greater the pressure is

Pressure

•Area affects pressure: the smaller the area of impact, the greater the pressure

SI Units

• Pressure = Force/Area• Force is measure in newtons (N)• Area is measured in m2

• The SI unit for pressure is the pascal (Pa)

• Pa=N/m2

Factors that affect gas pressure

• Factors that affect the pressure of an enclosed gas are its temperature, its volume, and the number of its particles

Temperature

• Raising the temperature of a gas will increase its pressure if the volume of the gas and the number of particles are constant• Think of a car tire on the road

Temperature and gas

Volume

• Reducing the volume of a gas increases its pressure if the temperature of the gas and the number of particles are constant.• Empty plastic bottle

Volume and gas pressure

Number of particles

• Increasing the number of particles will increase the pressure of a gas if the temperature and the volume are constant

Complete your workbook up to number 18 on page 26.

Complete the section assessment on page 74 in your book

Due tomorrow