DENSITY AND SPECIFIC GRAVITY

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DENSITY AND SPECIFIC GRAVITY

• A property of matter representing the mass per
  unit volume
• g/ml liquid -grams/milliliters
• g/cm3 -solid -grams/centimeters cubed
• 1ml 1cm3
• Must be in grams, centimeters, and milliliters
  no other units allowed

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To Find the Mass (numerator)

• Grams -mass
• -solid -place item on balance scales
• -liquid 1. find the mass of an empty
  cylinder
• 2. find the mass of the cylinder with
  the liquid in it
• 3. subtract the two readings the
  mass of the liquid

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To Find Volume (denominator)

• Volume -ml or cm3
• Use a cylinder for liquid and read the meniscus
  (lowest level of liquid in the cylinder)

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Volume of an Irregular Solid

• Use water displacement for a solid
• 1. put water in a cylinder and read
• 2. drop a solid in the water and read again
• 3. subtract the two readings

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continued

• Water weighs 1 gram per milliliter
• Waters mass is 1 gram per milliliter
• Waters density is 1 gram per milliliter
• Anything more dense than 1 gram per milliliter
  will sink in water
• Anything less dense than 1gram per milliliter
  will float on water

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Volume of a Regular Solid

• Volume for a regular solid
• using a meter stick, measure the height, width,
  and length
• H x W x L the volume
• 1 side x 1 side x 1 side the volume of a
  cube
• if all the sides are the same the side
  cubed (g/cm3)

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Review

• Volume of a rectangle
• L x W x H
• Volume of a cylinder (radius diameter/2)
• pi x R2 x H
• Volume of a sphere
• 4/3 x pi x R2 (radius circumference/pi/2)
• Check in passbook for equations

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Label for Density

• So, Density g/cm3 or g/ml

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Problems to Solve

• Density ?
• cm3 5
• g 15
• (per means to divide) g/cm3
• Grams ?
• density 6 g/ml
• ml 2

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• Volume 50cm3
• Mass 100grams
• What is the density of this object
• Volume 32 liters
• Mass 40 centigrams (must change
  centigrams to grams before completing
  the problem)

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• Volume reading in cylinder
• water only 4ml
• water with rock 8ml
• mass 12 g
• Will it float or sink in water?
• What is the density?