8th grade ch. 1 sec. 2 measuring matter

Ch. 1Ch. 1Sec. 2 Sec. 2

Measuring Measuring MatterMatter

weightweight• depends on force of gravity

mass• Unlike an object’s weight, an

object’s mass will not change if the force of gravity on it changes.

definition formula SI units

massmass

measure of how much matter an object contains

• kilogram (kg)• gram (g)

volumevolume

amount of space that matter occupies

length X width X height

(l.w.h)

• cm3 (solids)• liter (L)• milliliter (mL)

densitydensity

measure of how much mass is in a given volume

mass

volume

• g/cm3

• g/mL

Volume is found by multiplying the measurements of length, width, and

height.

L x W x HL x W x H

Answer= cubic centimeters

(cm3)

How can you measure the volume of an object with an

irregular shape, such as a rock?

• One way is to put the object in a graduated cylinder containing water and measure the change in the volume of the water.

• Answer is in mL not cm3

density

• density of water = 1.0 g/mL

(1.0 g/cm3)

A small block of wood floats on water. It has a volume of 25 cubic

centimeters and a mass of 20 grams. What is the density of the wood?

• Density= Mass

Volume

• Density= 20 g

25 cm3

• Density= 0.8 g/cmDensity= 0.8 g/cm33

Density ProblemsCoin Mass

(g)Volume

(cm3)

Density

(g/cm3)

A 2.5 g 0.5 cm3

B 4.8 g 0.08 cm3

C 7.2 g 2.4 g/cm3

Object Mass (g) Volume (cm3) Density (g/cm3)Whole Whole

Wooden stickWooden stick

Piece 1

Piece 2

Whole Whole Modeling clayModeling clay

Piece 1

Piece 2

Whole CrayonWhole Crayon

Piece 1

Piece 2

RockRock

MarbleMarble

Activity pg. 28 - Making Sense of Density Activity pg. 28 - Making Sense of Density

1.0 g/mL(1.0 g/cm3)

density of water

weightweight

• depends on force of gravity

massmass• Unlike an object’s weight, an object’s ____

will not change if the force of gravity on it changes.

massmass• measure of how much matter an object contains

volumevolumeamount of space that

matter occupies

densitydensitymeasure of how much

mass is in a given volume

Which liquid has the greatest density? Water, corn syrup, or

vegetable oil?• Hypothesis: I

predict that the ________ will have the greatest density because _______________.

• Observations: ______________

3. Corn syrup

2. Water

1. Vegetable oil

3.

2.

1.

Before

After

Matter of DensityObject Floats or sinks Density compared

to water

Marble

Wood

Ironwood

Japanese yen

Granite

Pumice rock

Penny