Earth Science Rocks! Warm up Feb. 4

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Earth Science Rocks!Warm up Feb. 4

• Question Why does a hot air balloon rise?

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iPad information

• School appropriate backgrounds

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Earth Science Rocks!

• MYP Unit Question What should I wear today?
• Area of Interaction Environment
• Learner Profile Communicator

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Earth Science Rocks!

• Standard Understand how the distribution of
  land and oceans affect climate and weather.
• Learning Target Today I am learning about air
  pressure because it is a factor in determining
  weather.

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Air PressureActivating Strategy
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Air facts

• Air has mass.
• Air takes up space.
• Air has density.
• Air pressure is the weight of a column of air
  pressing down on an area.

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Air Pressure

• Air pressure is the result of the column of air
  that is above you.
• There is so much air above you that at sea level
  you have 14.7 lbs/in2 pushing on you.

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Pressure analogy

• Imagine a stack of books. The bottom book feels
  all the weight of the all the books stacked above
  it, while the second one up feels slightly less
  weight. The higher in the stack, the less
  pressure one would feel.

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Why are we not crushed by air pressure?

• Air pressure is equal in all directions.
• So air pushes equally in all sides of us. The
  forces are balanced!

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Altitude and Pressure

• Altitude (or elevation) is the distance above sea
  level.
• The higher the altitude, the less air there is
  above you. So as altitude increases, air
  pressure decreases.

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Altitude and Density

• As the air pressure decreases, the density of the
  air decreases. The air particles are not
  squashed together as tightly the higher one goes.
• The air at sea level and at 6km has the same 21
  oxygen, but at 6km there are fewer molecules, so
  you take in less oxygen with each breath.

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Air Pressure

• As Air Pressure decreases, so does density.

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Measuring Air Pressure

• We use barometers to measure air pressure.
• Mercury barometer a glass tube sealed at the
  top partially filled with mercury.
• Air pressure pushing on the mercury in the dish
  causes the mercury to rise and fall in the tube.

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Mercury Barometer
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Aneroid Barometers

• Aneroid Barometer Works without liquid. Has an
  airtight metal can that is sensitive to changes
  in air pressure. This chamber is connected to a
  dial.

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Units of Air Pressure

• TV weather stations and aviation use inches of
  mercury.
• Meteorologists (and the NWS) use millibars, an
  SI unit.

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Egg in bottle

• Fire heated air, causing it to expand and leave
  the bottle.
• When fire went out, temperature cooled, molecules
  condensed, changing air pressure.
• Since the pressure outside bottle was higher, the
  higher pressure tried to get in the bottle.
• Since the egg is squeezable, it got pushed into
  the bottle by the air.

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Crushing cans with Air Pressure

• You explain it!
• Hint Air moves from high to low pressure.

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Atmosphere
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Create a 4 square

• Air pressure notes
• Egg in a bottle
• Crushing cans with air pressure
• What I learned today