Matter

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Matter

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Matter

• Makes up all of the objects and living organisms
  in the universe
• Anything that has mass AND takes up space
• Light and sound are NOT matterwhy?
• Matter is made of particles called atomsmatter
  IS atoms.
• Atoms have mass
• Air is made of atoms
• Sound and light waves traveling through air do
  not have mass OR take up space

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Three (of five) forms of Matter

• Solid matter - has a fixed volume and shape of
  the object or substance.
• Liquid matter - has a definite volume but not a
  definite shape.
• Gas matter - does not have a definite shape and
  volume.

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Mass

• A physical property of matter
• Measure of how much matter an object contains
• Standard unit Kilogram (kg)
• 1 kg 1000 grams (g)
• Ex grapefruit 500 g, penny 2-3 g
• Measure mass using a triple-beam balance

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Mass vs Weight
Mass is a measurement of the amount of matter something contains Weight is the measurement of the pull of gravity on an object.
Mass is measured by using a balance comparing a known amount of matter to an unknown amount of matter. Weight is measured on a scale.
The Mass of an object doesn't change when an object's location changes. Weight does change with location.
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• A triple beam balance compares a known mass to an
  unknown mass, so it is unaffected by gravity.
• A scale measures weight, the triple beam balance
  gives a true measure of mass.
• On the moon the mass on the left side of the
  balance may 'exert less force', but then less
  force will be needed to balance it.

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Weight and Gravity

• Recall
• Gravity is the force that pulls two masses toward
  each other
• Standard unit Newton (N)
• Common unit Pound (lb)
• Force mass acceleration (Fma)
• Newton kilogrammeter/second2 (N kg m/s2)
• Weight is a force!
• Mass is amount of matter of an object, weight is
  how strongly gravity is pulling on that matter

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F GM m/r2

• What will cause the force of attraction to
  increase or decrease?
• If either mass increases the force of attraction
  increases proportionally. Since the moon has 1/6
  the mass of earth, it would exert a force on an
  object that is 1/6 that on earth.
• Why is the 1/r2 factor so important?
• This is an inverse square relationship which
  seems to show up a lot in physics. How does it
  affect the force?
• When r1 the value 1/r 2 is 1.0, but at r10 it
  deceases to 1/100. That means gravity gets weak
  'quick' as we move away from the earth.

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Compute Mass and Weight

• If a cube has a mass of 90.91 kilograms and a
  weight of 200 pounds on Earth, what will its mass
  and weight be on another planet?
• The Moon has a gravity that is 0.165 of Earth's.
• The cube will have a weight of
• ________________ pounds
• and a mass of
• _______________ kilograms
• Jupiter has a gravity that is 2.34 times greater
  than Earth'sweight? Mass?

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Compute Mass and Weight

• On the moon
• Weight 33 lb
• Mass still 90.91 kg!
• On Jupiter
• Weight 468 lb
• Mass 90.91 kg

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Volume

• Volume is the amount of space an object occupies.
  
• The volume of an object can be calculated
  geometrically using mathematical equations or by
  measuring liquid displacement.
• Measure the volume of a cube using the formula
  V(side)x(side)x(side) (length times width times
  height) and by using a graduated cylinder to
  measure liquid displacement.

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• Volume L x W x H (cm3 or in3 etc.)
• The side of the cube is approximately 3.1
  centimeters. How many inches does this convert to
  (use 2.54 cm. 1 inch)?

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Measure Volume by Displacement

• What was the amount of water displaced by the
  object? (1 ml 1cm3)

                                Before
                                             
  After
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Density

• Each box has the same volume.
• If each ball has the same mass, which box would
  weigh more? Why?

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Density

• The box that has more balls has more mass per
  unit of volume. D m/V
• The density of a material helps to distinguish it
  from other materials.
• Mass grams (g) or kilograms (kg)
• Volume cubic centimeters (cm3) or cubic meters
  (m3)
• Density grams/cubic centimeter (g/cm3) or
  kilograms/cubic meter (kg/m3)

Periodic Table masses One gram is about
600,000,000,000,000,000,000,000 amu (a 6 followed
by 23 zeros) 6 x 1023 amu.
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Density of a Liquid

• Problem You are given two unknown liquids. Find
  the density of each. Materials 100ml graduated
  cylinder, triple beam balance, calculator, 2
  unknown liquids.
• Procedure
• 1) Find the mass of the empty graduated cylinder.
  
• 2) Pour unknown liquid 1 into the graduated
  cylinder to the 50 ml. level.
• 3) Find the mass of the graduated cylinder with
  50ml of unknown liquid 1.
• 4) Repeat steps 1-3 for unknown liquid 2.

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Density of a Liquid

• Liquid 1
• Given Mass of empty graduated cylinder 78
  grams
• Mass of graduated cylinder with unknown liquid
  1 128 grams.
• Find
• a) Mass of just the liquid ____ b) Volume of
  liquid_____c) Density of liquid 1 ____

• Liquid 2
• Given Mass of empty graduated cylinder 78
  grams
• Mass of graduated cylinder with unknown liquid
  2 117.5 grams.
• Find
• a) Mass of just the liquid ____ b) Volume of
  liquid _____c) Density of liquid 2____

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What is the Liquid?
Substance Density (gm/cu.cm)
Water 1.00
Cooking oil 0.92
Sea Water 1.025
Carbon tetrachloride 1.58
Benzene 0.87
Glycerin 1.26
Methanol 0.79

• What is each liquid? Using the table below it is
  now possible for you to determine what each
  liquid is.
• Densities for some common liquids are

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Extension Air Pressure

• Air pressure is the force exerted by the weight
  of a column of air above a particular location.
• Imagine a sealed container full of air

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• Change the pressure
• Increase the density of the air by either putting
  more air molecules into the container or reducing
  the volume of the container.
• Therefore, changes in air pressure can come about
  by changes in air density

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• Atmospheric pressure is defined as the force per
  unit area exerted against a surface by the weight
  of the air above that surface.

• If the number of air molecules above a surface
  increases, there are more molecules to exert a
  force on that surface and consequently, the
  pressure increases.
• The opposite is also true, where a reduction in
  the number of air molecules above a surface will
  result in a decrease in pressure.

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Air Pressure Altitude

• Air pressure decreases as one moves upward
  through the atmosphere because the length of the
  column of air shortens and hence there is less
  mass above a given location.

• Because air is highly compressible, the air is
  closely packed together near the surface (high
  density) and less densely packed aloft