Scien

ce

by Kathy Furgang

Make a KWL Chart Before you read this book, make a KWL chart.

~ Write what you know about matter in the K column.

Write what you want to know about matter in the W column.

K W I L

After you read this book, finish the KWL cha rt. Write what you lea rned in the L column of the chart.

- magneti~

-densitY~ chemical change-

I '

--.!teonsidad .- .... ca~bio quimico •

'iii7"'I boiling point -- -""""- volume

Do you understand? ~ Write or ~ draw your answers. 1. How can you make a physical change

to a &-c,.? List three ways. 2. Where is the magnetic field of a

IIf.:!I ~ I strongest? 3. How can you find the density

ofa

4. Write About Science Think about the difference between a chemical change and a physical change.

Write how a log can go through a physical change a nd a chemical change. Use the pictures to help you.

by Kathy Furgang

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Properties of Matter Mauer is all around you. Maller is anything that

has mass ond takes up space. Mass is the amount

of matter that makes up on object.

Matter has properties thaI help you tell one kind

of matter from another. A property is a trait of on

object. Color, shape, and size arc some properties of

matter. Texture, odor, and taste are others. Texture

tells if matter is smooth or rough, or hard or soft.

The attroction of some matter to magnets is

another property. Iron and nickel ore metals

that hove this property.

They ore magnetic.

Some properties of matter co n be measured.

Mass can be measured.

Weight is a measure of the puB of gravity

between an object a nd the ground. An object's

weight on Earth is different than its weight on the

moon. Th is is because the pull of gravity is different

on the moon than it is on Ea rth.

Volume is the amount of space that matter takes

up. The property thot compares an object's moss to

its volume is called density . Objects with a lesser

density than water will float in water.

--.,'.

States of Matter All matter is made up of particles

too small to see. The slate of

matter depends on how

particles inside it are arranged

and move. Three states of matter

are solid, liquid, and gas.

Particles in a solid are close

together. They move back and

forth. A solid has a definite shape.

Most solids take up a definite

amount of space.

Particles in a liquid slide

post each other. A liquid takes

the shape of the object it is in.

But a liquid takes up a definite

amount of space.

Particles in a gas are far apart.

They move around quickly. A gas

does not have its own shape.

It takes the shape of the object

itisin.

Change of State Adding or taking away energy can make matter

change state. On Earth water is found as a solid, a

liquid, and a gas. If you heat frozen water, it melts

to become liquid water. Liquid water can boil to

become water vapor, or gas.

The melting point is the temperature at which

a substance changes from a solid to a liquid.

The boiling point is the temperature at which

a substance changes from a liquid to a gas.

Substances have different melting points and

boiling points.

Measuring Mass The mass of on object will change only if matter

is added or taken away. A flat sheet of foil can be

shaped into a boll. The foil has the same moss

when it is flat and when it is a ball. [t is still the

some amount of matter.

Mass is measured with a tool coiled a balance.

You can use a balance to compare the mosses

of two objects. Put on object on each pan of the

balance. The pan that is lower holds the object

with the greater mass.

A shoet of foil ond the some foil shaped into a boll have the some moss.

A balance can also measure moss in units. Moss

is measured in metric system units called grams (g).

The system is hosed on tens. For example, 1,000

milligrams (mg) ore equal to 1 gram. There are

1,000 gra ms in 1 kilogram (kg).

To measure the moss of an object, place it on one

side of the balance. Add gram units to the other side

until the two sides ba lance.

The Law of Conservation of Moss says that the

parts of an object have the some total moss as the

whole object. Measure the mass of a toy. Take the

toy apart and measure the moss of all the parts.

The mass of the parts will equa l the mass of the toy

put together.

A balonce meawres or campare$ the masses of objects.

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Measuring Volume The amount of space that matter takes up is

the propcrty of volume . You can use a ruler to measure the volume of a solid object like a cube.

You multiply the length, width, and hcight of the

solid object.

The equation shows how to find the volume of a

cube that is 2 cm on each side.

volume = length x width x height

volume = 2 cm x 2 cm x 2 cm

volume = 8 cmJ (8 cubic centimeters)

"

The volume of a liquid can be found by using a graduated cylinder. The unit of measure for volume

in the metric system is the liter (L). There are 1,000

milliliters (mL) in 1 liter.

A graduated cylinder can help you measure the

volumes of solids too. It is hard to measure the

length, width, and height of a ball because it is

round. Instead, put the ball in a graduated cylinder

that has water in it.

The water level rises when you put the ball in.

The amount the water rises is equal to the volume

of the ball.

'. • • • •

• • •

• • • • • • • •

Measuring Density The amount of mass in a certain volume of

motter is co iled density. Density is a property of

motter. Divide the moss of an object by its volume

to find the density.

The density of on object can tell you whether the

oblect will sink or float. Some liquids have greater

density than others. For example, water will float

on top of corn syrup. That is because corn sy rup

has a greater density than water.

The picture helps you compore the densi ties of

substances. A substa nce at the bottom of the glass

has a greater density than the one at the top. A

substance at the top has a lesser density thon the

one at the bottom.

Which liquid in the picture has the greatest

density? Which sol id hos the least?

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MagnetismSome matter, such as iron, is attracted to

magnets. Iron is magnetic. Magnetism is a

force that acts on moving electric charges and

magnetic materials.

A magnetic field is the space around a magnet

that has a pulling force. The ends of a magnet are

called its poles. The magnetic field is strongest at

the poles.

Opposite poles attract each other. The north pole

of one magnet attracts the south pole of another.

Like poles repel, or push away from, each other.

Two north poles repel each other.

A horseshoe magnet has a magnetic field that is U-shaped.

Magnetic poles are at the ends of the magnet. That is where the magnetic pull is strongest.

S N S N

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Magnetic Compass Magnets are not the only things with a magnetic

field. Earth has a magnetic field too. The south pole

of a magnet will pull toward Earth's magnetic

north pole.

A compass is a tool that has a small magnetic

needle. The needle spins until it points toward

Earth's magnetic north. A compass helps you find

where north is.

A compass will not work right if it is too close to a

magnet. The needle of the compass will react to the

magnet's pull instead of Earth's magnetic pull.

®

Physical Changes There are many ways to change matter. A

physical change is a change in the size, shape, or

state of matter. The particles that make up matter

do not change. But the way the particles are

arranged may change.

Cutting a sheet of paper is a physico I change.

The paper does not change into other matter. It is

still poper. Breaking a pencil in half is also a

physico I change. Each piece is made of the some

matter as the whole pencil.

Making a mixture is olso a physical chonge. The

parts that make up the mixture ore the same after

mixing as before.

Knitting a ball of yam into o scarf is a physical change.

Chemical Changes A chemical change produces a different kind

of matter. Particles of one or more substances are

chonged. They form particles of new substances

with different properties.

Rust will form on on iron nail that is left in a wet

place. Rusting is a chemical change. Rust has

different properties than the iron that formed it.

Food rotting is also a chemical change. Burning a

log and baking a cake are other examples.

Changes in smell or color

are signs of a chemical change.

Giving off heat and forming

bubbles are others.

Vinegar added to baking soda reads in a chemical change. One new substance that farms is carbon diOJlide in the farm of gas bubbles.

Glossary boiling point

chemical c hange

density

magnetism

property

volu.m e

the temperature at which a substance cha nges from a liquid to a gas

a change in matter that produces one or more completely d ifferent kinds of matter

property of matter that

Did you understand? CJ' Write or " draw your a nswers. 1. What does the law of Conservation of

Mass mean?

2. At what point does a substa nce cha nge from a liquid to a gas?

3. How can you measure the volume

ofa @ ?

Physical Changes Make a cha rt like the one shown.

Physical Changes to Paper How I Changed the Paper

How It Looked

Look at a clean piece of poper. Think of ways to make physical changes to the paper.

~ Write or if draw your ideas in your chart. Then tryout your ideas. Compare your results with those of a partner.

~ Tell why the cha nges you mode are physical changes.

What is the volume of a box? To measure the volume of a box, multiply its length, height, a nd width.

height " 2 em heigllt ,,? ern It. " 3 ern length = ? ern

Totol volume is 211 em'

The volume of Box A is 2 em x 3 em x 4 em, or 24 em3•

Measure Box B using a metric ruler.

~ Write your a nswers.

1. What is the volume of Box B? Show your work.

2. Which has a greater volume, Box A or Box B?

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PEARSON -

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