Students will define density.Students will explain how to find the

density of a solid or a liquid.

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DensityVolumeMass

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Which do you think is heavier, a kilogram of cotton or a kilogram of iron? They both weigh the same amount.

However, a kilogram of cotton takes up a greater amount of space, or volume. A kilogram of iron takes up less space

because iron has a much greater density than cotton does.

Density is the mass per unit volume of a substance.

Substances that are very heavy for their volume are called dense substances.

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You can find the density of a substance by finding the mass of a unit volume of the substance.

Units of density include units of mass and volume.

Mass is measured in grams. The volume of solids is

measured in cubic centimeters or mL

Therefore, the density of any substance can be given in grams per cubic centimeter, or g/cm³. For example, water has a density

of 1 g/cm³. 5

What is density?

What are the units for density??

Why are the units for density grams/mL or cm3?

Density is a physical property of matter. Every kind of matter has a density that,

can be measured. The density of a pure substance is

always the same. Density does not depend on size or

shape of the substance. Density can be used to help identify

differ kinds of matter. If you know the density of a sample,

you can identify it.

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To find the density of a material, you must measure both mass and volume.

You can find density by dividing the mass by the volume. Remember that mass is measured in grams. Volume is measured in cubic centimeters or

milliliters, so density is expressed in grams per cubic centimeter.

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Density = mass/volume

Density = grams/mL

You can find the density of any solid if you know its mass and its volume. You I can use a balance to find the mass of a

solid. You can, find the volume of a rectangular solid

by multiplying its length by its width by its height by using a ruler

To find the density of a solid, divide its mass by its volume.

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density = mass ÷ volumedensity = 270 g ÷ 100 cm³ density = 2.7 g/cm³

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1. Density is the ____ per unit volume of a substance.

2. The units of _______ are grams per cubic centimeter.

3. What measurements must be known in order to find the density of a substance?

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1. Mass2. Density3. Mass and volume

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1. What is the volume of the bar? 2. If the bar has a mass of 500 g, what is

its density?

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10 cm

2 cm

1. 400 cm³2. 500 g ÷ 400 cm³ = 1.25 g/cm³

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