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Matter
• Matter is ANYTHING that has mass and takes up space.
Matter Is All Around Us
• Where is it in our classroom?
• Lab Tables
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Chairs
People
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Pencils
Books
• Even the air.
All Matter Has Mass
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How do we find out how much matter and object contains?
• Measure the mass.
What tool do we use?
What unit?
Grams (g)
Mass vs. Weight
• The mass of an object is always the same no matter where it is located.
• Weight is a measure of the amount of gravity exerted on an object.
• We weigh less on the moon than on earth because the moon experiences less gravity. Our mass is the same.
All Matter Has Volume
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Volume
• The amount of space the matter occupies
What tools do we use?
What Units?
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Liters (L)
OR
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Cubic centimeters (cm 3 )
Remember 1mL = 1cm 3
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Density
Do all things that are the same volume have the same mass?
• Density is the amount of matter in a given space.
• Which is more dense: a 1m 3 box of feathers or a
1m 3 box of pennies?
• Pennies – they’re not heavier , they’re more dense
Calculating Density
• Density = Mass
Volume
M
D X
V
• The unit for density is g/cm 3 or g/ml
• Density is useful for identifying substances for two reasons:
• Density stays the same for any SIZE piece of something
• The density of one substance is usually different from that of another substance.
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Fool’s Gold?
To make sure you hadn’t found more fool’s gold (iron pyrite), you could compare the density of your nugget to the know densities on the chart.
• D= M/V
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D= 96.6/5
D= 19.32 g/cm 3
Mass= 96.6g
Volume= 5cm 3
Substance
Iron Pyrite
Gold
Density (g/cm 3 )
5.02
19.32
BrianPop Review
Try it out!
A glass marble has a volume of 5 cm3 and a mass of 13 g. What is the density of glass?
What do you know?
Volume = 5 cm 3 , mass = 13 g
Write the formula:
D = m/v
Substitute into the formula:
D = 13g
5 cm 3
Calculate:
D = 2.6 g/cm 3
Check that your units agree:
Unit is g/cm 3 .
Unit of density is g/cm 3 . Units agree.
Answer:
D = 2.6 g/cm 3
Practice Problems
1. A lead sinker has a mass of 227 g and a volume of
20 cm 3 . What is the density of lead?
2. A glass of milk has a volume of 100 cm 3 . If the milk has a mass of 103 g, what is the density of milk?
Answers:
1. 11.35 g/ cm 3
2. 1.03 g/ cm 3
