Physical Science Changes in Matter BenchmarksIV.2.MS.1IV.2.MS.2IV.2.MS.3.

Physical SciencePhysical ScienceChanges in MatterChanges in Matter

BenchmarksBenchmarksIV.2.MS.1IV.2.MS.1IV.2.MS.2IV.2.MS.2IV.2.MS.3IV.2.MS.3

BenchmarksBenchmarks Describe common physical changes in Describe common physical changes in

matter: evaporation, condensation, thermal matter: evaporation, condensation, thermal expansion, contraction. (IV.2.MS.1)expansion, contraction. (IV.2.MS.1)

Describe common chemical changes in Describe common chemical changes in terms of properties of reactants and terms of properties of reactants and products. (IV.2.MS.2)products. (IV.2.MS.2)

Explain physical changes in terms of the Explain physical changes in terms of the arrangement and motion of atoms and arrangement and motion of atoms and molecules. (IV.2.MS.3)molecules. (IV.2.MS.3)

3 States of Matter3 States of Matter

There are 3 major states of matter, they There are 3 major states of matter, they are…are…SolidsSolidsLiquidsLiquidsGassesGasses

In all three states of matter, molecules are In all three states of matter, molecules are in constant motion. in constant motion.

And yet another phase of matter…And yet another phase of matter…

Plasma is another phase of matter that is Plasma is another phase of matter that is sometimes recognized by scientists. sometimes recognized by scientists. It is a state above the gas phase. It is a state above the gas phase.

Click the link to see another explanation of the Click the link to see another explanation of the states of matter. states of matter. http://www.chem4kids.com/files/matter_states.htmlhttp://www.chem4kids.com/files/matter_states.html

SolidsSolids

In a In a solidsolid, relatively strong forces are , relatively strong forces are exerted between the molecules, so the exerted between the molecules, so the molecules of the material vibrate molecules of the material vibrate slowly. slowly.

Solids, therefore, have a definite shape Solids, therefore, have a definite shape and volume.and volume.

LiquidsLiquids

When heat energy is added, the When heat energy is added, the molecules vibrate faster as they absorb molecules vibrate faster as they absorb the energy. the energy.

At the melting temperature of the At the melting temperature of the material, the molecules have gained material, the molecules have gained enough energy, so that they can slip enough energy, so that they can slip and slide past each other. and slide past each other.

The material is now a The material is now a liquidliquid..

GassesGasses

Liquids still have a definite volume, but Liquids still have a definite volume, but take the shape of their container. take the shape of their container.

When more heat energy is added, the When more heat energy is added, the motion of the molecules within the motion of the molecules within the liquid increases, until some of the liquid increases, until some of the molecules overcome the forces, molecules overcome the forces, becoming a gas. becoming a gas.

The liquid has now evaporated to a The liquid has now evaporated to a gasgas..

The reverse is also trueThe reverse is also trueGas molecules are separated by Gas molecules are separated by

relatively great distances and move relatively great distances and move about freely. about freely.

Gases take the shape and volume of Gases take the shape and volume of their container. their container.

Conversely, when enough energy is Conversely, when enough energy is lost from gas molecules, they lost from gas molecules, they condensecondense into the liquid phase. into the liquid phase.

more heat energy less heat energy

+E -E

warmer colder

GasGas (water vapor)

LiquidLiquid(water)(water)

SolidSolid(ice)(ice)

No definite shapeNo definite shape No definite shapeNo definite shape Definite shapeDefinite shape

No definite volumeNo definite volume Definite volumeDefinite volume Definite volumeDefinite volume

PlasmaPlasma BECBEC

Expand

Contract

Condensation Freezing

Evaporation Melting

States of Matter

Thermal ExpansionThermal Expansion

As a solid is heated, particles move faster As a solid is heated, particles move faster and faster and vibrate against each other and faster and vibrate against each other with more force. with more force.

As a result, the particles spread apart slightly As a result, the particles spread apart slightly in all directions and the solid expands. in all directions and the solid expands.

The same effect also occurs in liquids and The same effect also occurs in liquids and gases.gases.

Thermal ExpansionThermal Expansion

Almost all matter expands as it gets Almost all matter expands as it gets hotter and contracts as it cools. hotter and contracts as it cools.

This characteristic of matter is called This characteristic of matter is called thermal expansionthermal expansion. .

This happens because in a solid, forces This happens because in a solid, forces between the particles hold them between the particles hold them together.together.

Thermal expansionThermal expansion

Since this phenomenon Since this phenomenon occurs in bridges, occurs in bridges, expansion joints allow expansion joints allow bridges to expand in warm bridges to expand in warm weather without cracking. weather without cracking.

Can you imagine the Can you imagine the effect that thermal effect that thermal expansion and expansion and contraction might have contraction might have on our roads? on our roads?

Heat and Phases of MatterHeat and Phases of Matter

Heat affects Heat affects the phases the phases of matter. of matter. View this View this video clip to video clip to see how. see how.

IntroductionIntroduction

There are two types of properties of There are two types of properties of matter, they are physical properties and matter, they are physical properties and chemical properties. chemical properties.

There are also two types of changes in There are also two types of changes in matter they are physical changes and matter they are physical changes and chemical changes. chemical changes.

Let’s talk about physical properties first. Let’s talk about physical properties first.

Physical PropertiesPhysical Properties

A A physical propertyphysical property is any is any characteristic of a material that one can characteristic of a material that one can observe easily observe easily without changing the without changing the substances that make up the materialsubstances that make up the material. .

Every substance has physical Every substance has physical properties that distinguish it from other properties that distinguish it from other substances.substances.

Physical PropertiesPhysical Properties

Physical property examples…Physical property examples… shapeshape SizeSize ColorColor SmellSmell TemperatureTemperature VolumeVolume DensityDensity melting pointmelting point boiling pointboiling point state of matter.state of matter.

Physical ChangesPhysical Changes

A change in physical properties is A change in physical properties is called a called a physical changephysical change..

Physical changes do not alter the Physical changes do not alter the identity of a substance.identity of a substance.

Pounding, pulling, cutting, dissolving, Pounding, pulling, cutting, dissolving, melting, or boiling do not produce a melting, or boiling do not produce a new substance with new properties, so new substance with new properties, so they are all physical changes.they are all physical changes.

Physical Change ExamplePhysical Change Example

For example if you take a piece of For example if you take a piece of paper and tear it into pieces you still paper and tear it into pieces you still have paper. It may be smaller, but it’s have paper. It may be smaller, but it’s still paper. still paper.

You could dye the paper and make it You could dye the paper and make it another color, but it’s still paper. another color, but it’s still paper.

You have only changed it physically. You have only changed it physically.

Physical ChangesPhysical Changes

When trying to identify a physical change, When trying to identify a physical change, it is important to know that physical it is important to know that physical changes can be reversed. changes can be reversed.

For example…For example…Pieces of paper can be reformed into a new whole Pieces of paper can be reformed into a new whole

sheet.sheet.Ice can be melted, or boiled and then refrozen. Ice can be melted, or boiled and then refrozen.

Physical Changes of WaterPhysical Changes of WaterFreezingFreezing-liquid to a solid; this change requires -liquid to a solid; this change requires

coolingcoolingMeltingMelting-solid to a liquid: this change is speeded up -solid to a liquid: this change is speeded up

by heating. by heating. CondensationCondensation-gases change to a liquid; this -gases change to a liquid; this

change requires cooling.change requires cooling.Vaporization/EvaporationVaporization/Evaporation-liquid changes to gas; -liquid changes to gas;

this change is speeded up by heating.this change is speeded up by heating.SublimationSublimation-gas changes to a solid or a solid -gas changes to a solid or a solid

changes to a gas without passing through the changes to a gas without passing through the liquid state (e.g., dry ice, solid to gas)liquid state (e.g., dry ice, solid to gas)

What Do You Think?What Do You Think?

Can you name Can you name this physical this physical change of water? change of water?

Here’s a hint: The Here’s a hint: The water is changing water is changing from the gas to from the gas to the liquid phase. the liquid phase.

What Do You Think?What Do You Think?

Can you name Can you name this physical this physical change of water? change of water?

Here’s a hint: The Here’s a hint: The water is changing water is changing from the liquid to from the liquid to the gas phase.the gas phase.

Review VideoReview Video

That was a lot of That was a lot of information. Let’s information. Let’s review physical review physical properties and properties and physical changes physical changes with a look at this with a look at this video clip on video clip on states of matter. states of matter. (18 min)(18 min)

Chemical Properties/ChangesChemical Properties/Changes

Substances Substances can change can change their their identities, identities, for example, for example, fireworks fireworks explode,explode,


matches matches burn burn


Food cooksFood cooks


And iron And iron rustsrusts


Burned toast, burned soup, and burned Burned toast, burned soup, and burned steak all smell burned. The smell is steak all smell burned. The smell is different from the smell of bread, soup, or different from the smell of bread, soup, or steak. steak.

The odor is a clue that a The odor is a clue that a new substancenew substance has been produced. has been produced.

Chemical PropertyChemical Property

A A chemical propertychemical property is a characteristic of is a characteristic of a substance that a substance that indicates if it can indicates if it can undergo a certain undergo a certain chemical change.chemical change.

Click the picture for a Click the picture for a video clip about video clip about chemical properties. chemical properties.

Chemical ChangeChemical Change A change of one substance in a material to a A change of one substance in a material to a

different substance is a different substance is a chemical changechemical change. .

In some chemical changes a rapid In some chemical changes a rapid production of energy, such as the production production of energy, such as the production of heat, light, sound or gas bubbles occur. of heat, light, sound or gas bubbles occur. These things indicate that a chemical change These things indicate that a chemical change has occurred. has occurred.

BurningBurning and and rustingrusting are chemical changes are chemical changes because different substances are produced.because different substances are produced.

Chemical ChangeChemical Change A baked cake no longer resembles its A baked cake no longer resembles its

ingredients of flour, eggs, butter, and sugar, ingredients of flour, eggs, butter, and sugar, because the reactants have undergone a because the reactants have undergone a chemical change. chemical change.

A A chemical reactionchemical reaction is simply breaking substances ( is simply breaking substances (reactantsreactants) apart ) apart and making new ones (and making new ones (productsproducts) from the pieces.) from the pieces.

reactantsproduct

Chemical ChangesChemical Changes

When trying to identify a chemical change, When trying to identify a chemical change, it is important to know that chemical it is important to know that chemical changes can NOT be reversed. changes can NOT be reversed.

For example…For example…A cake can not be broken down into eggs, sugar, A cake can not be broken down into eggs, sugar,

flour, and butter.flour, and butter.You can not un burn a piece of wood. You can not un burn a piece of wood.

Chemical ReactionsChemical Reactions

Those ingredients have been changed Those ingredients have been changed by a chemical reaction. by a chemical reaction.

A A chemical reactionchemical reaction is simply breaking is simply breaking substances (substances (reactantsreactants) apart and ) apart and making new substances (making new substances (productsproducts) ) from the pieces.from the pieces.


Whenever a chemical reaction takes Whenever a chemical reaction takes place, new substances, the products, place, new substances, the products, are made. are made.

These have very different properties These have very different properties from the original starting materials, the from the original starting materials, the reactants. reactants.

reactant + reactant = productreactant + reactant = product


This process involves the This process involves the rearrangement of atoms and molecules, rearrangement of atoms and molecules, and the making and breaking of and the making and breaking of chemical bonds.chemical bonds.

Closed SystemClosed System The mass remains constant, because a The mass remains constant, because a

chemical reaction is a closed system and no chemical reaction is a closed system and no matter is lost.matter is lost.

Closed systemClosed system: a system in which the total mass : a system in which the total mass of each element in the system remains constant of each element in the system remains constant before as well as after any kind of chemical or before as well as after any kind of chemical or physical change.physical change.

No matter is ever created or destroyed during No matter is ever created or destroyed during the change.the change.


Here’s a video Here’s a video clip that may clip that may explain explain chemical chemical changes more changes more clearly. clearly.

Physical & Chemical Changes Physical & Chemical Changes

Click the links to hear a science guys song Click the links to hear a science guys song on…on…Physical ChangesPhysical Changes


Physical Science Changes in Matter BenchmarksIV.2.MS.1IV.2.MS.2IV.2.MS.3.

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