What is Density?

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What is Density?

• Density is defined as the mass per unit of
  volume.
• Or
• How much mass we have in a given space.

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Density If you have ever been in a crowded movie
theater or shopping mall, you are familiar with
the idea of density. Picture your school
classroom with only five students in it. Now
think of that same classroom with 30 students in
it. The classroom is the same size in each case,
but the number of people is different. density
is a physical property of matter. Density
depends on both mass and volume. The Formula
used to find the density of an object is
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B.
A.
Which classroom has the smallest density?
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B.
A.

• In Science Density will tell us 2 things
• 1. How much mass we have in a given space. Look
  at the picture above.
• a. Which box do you think has the greatest mass?
• b. Which box do you think has the greatest
  volume?
• 2. Whether an object has a better chance of
  floating. Which one has a better chance of
  sinking?

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Will an object Sink or Float?
Float
Waters density 1.00 g/ cm
A.
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B.
Sink
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Water has a Density of 1 g/cm . Objects that
have a density greater than 1.00 g/cm will sink
like object B. Objects that have a density less
than 1.00 g/cm will float like object A.
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3
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• Practice
• An object has a mass of 25 grams and a volume of
  5 cm . What is the Density of the following
  object?
• A foam block has a mass of 10 grams and a volume
  of 40 cm . What is the density of this object?
• A Marble has a mass of 15 grams, and a volume of
  5 ml. What is the density of this object?
• A rock has a mass of 25 grams, and a volume of 75
  ml. What is the density of this object?

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1. An object has a mass of 25 grams and a volume of
   5 cm . What is the Density of the following
   object?

25 grams
D
3
5 cm
3
D 5 g/ cm
8
3
2. A foam block has a mass of 10 grams and a
volume of 40 cm . What is the density of this
object?
10 grams
D
3
40 cm
3
D .25 g/ cm
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3. A Marble has a mass of 15 grams, and a volume
of 5 ml. What is the density of this object?
15 grams
D
5 ml
D 3 g / ml
10
4. A rock has a mass of 25 grams, and a volume of
75 ml. What is the density of this object?
25 grams
D
75 ml
D .33 g / ml