Under Pressure
NC Science Olympiad Coaches Clinic
October 3, 2009
Dr. David G. Haase
Professor of Physics
NC State University
david_haase@ncsu.edu
9/7/09
NC Science Olympiad
Coaches Clinic 2009
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Overview
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Event Description
General event rules
Overview of the subject matter
Resources
Examples of questions or activities
Time for Questions
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NC Science Olympiad
Coaches Clinic 2009
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Event Description
• Students will demonstrate their
knowledge and skill related to the
physics of fluids.
• Experimental tasks and questions
including calculations
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NC Science Olympiad
Coaches Clinic 2009
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Under Pressure
• New event about the properties of
liquids and gases
• Not being used in Nationals
• Replaces Physics Lab C
• Division B (middle school) and Division
C (high school)
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NC Science Olympiad
Coaches Clinic 2009
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General Event Rules
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Teams of two
50 minutes
Combination of questions and activities
May bring non-programmable calculator and one (1) 8.5 x 11 in
page of notes front and back.
Students must bring and wear goggles during the event.
No other resource materials or electronic devices allowed
Where appropriate, materials data will be supplied, e.g. the
density of a certain solid.
No caustic or flammable liquids will be used in this event
Disclaimer: In all disputes the rules published on the NCSO web
page are the controlling authority.
9/7/09
NC Science Olympiad
Coaches Clinic 2009
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Content Matter
• Liquids and gases
• Density = mass/volume
• Floating and sinking
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NC Science Olympiad
Coaches Clinic 2009
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Content Matter
• Pressure P = Force/area
• Atmospheric pressure
• Pressure as a function of depth in a
liquid P = ρ g h
• Barometer
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NC Science Olympiad
Coaches Clinic 2009
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Content Matter
• Bernoulli’s Principle:
P1 + (½)ρ v12+ ρ g h1 = P2 + (½)ρ v22+ ρ g h2
• Buoyancy
• Buoyant Force Fbuoyant = ρVg
• Archimedes principle
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NC Science Olympiad
Coaches Clinic 2009
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Content Matter
• Pascal’s Principle
• Hydraulic and pneumatic devices
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NC Science Olympiad
Coaches Clinic 2009
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Content Matter
• Charles’s Law (law of volumes)
V1 V2
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T1 T2
• Boyle’s Law

9/7/09
P1V1  P2V2
NC Science Olympiad
Coaches Clinic 2009
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Content Matter
• Surface tension
• Capillary action
• Thermal expansion in liquids (Why do
icebergs float?)
• Viscosity and viscous forces
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NC Science Olympiad
Coaches Clinic 2009
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Resources
• Physics: Principles and Problems
http://highered.mcgraw-hill.com/sites/0078458137/
• Conceptual Physics by Paul Hewitt
http://www.conceptualphysics.com/
• MIT Open Courseware – Physics of Fluids
http://ocw.mit.edu/OcwWeb/hs/physics/g/index.htm
• High School Physics Lab
http://hsphysicslab.blogspot.com/
• The comPADRE Digital Library
http://www.compadre.org/
• Physical Sciences Resource Center
http://www.compadre.org/psrc/
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NC Science Olympiad
Coaches Clinic 2009
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Fluid Activities
• Measure the density and determine the
composition of an unknown object using
Archimedes method
• Predict whether an object will sink or float
• Measure the rate of air flow with a water
manometer made with clear plastic tubing
• Design and aluminum foil boat that can flow
at a certain amount of mass
• Calculate the amount of water displaced by a
floating object
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NC Science Olympiad
Coaches Clinic 2009
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Fluid Activities
• Straw and potato
• Demonstrate how to blow out a candle
with Bernoulli effect
• Measure the relative densities of two
liquids
• Predict the water pressure needed to fill
a tank
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NC Science Olympiad
Coaches Clinic 2009
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Fluid Activities
• Estimate the weight of an automobile by
measuring the tire tracks.
• Lift an object by inflating a balloon
• Measure or estimate the flow rate of liquid
through a tube
• Calculate the pressure on a submerged
object
• Measure the relative viscosity of two liquids
• Measure the compression of a gas under
changes in temperature or pressure
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NC Science Olympiad
Coaches Clinic 2009
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Fluid Activities
• Design a hot air balloon to lift a certain
weight
• Design a device to measure changes in
pressure
• Observe a fluid phenomena and explain
its physical basis
• Build a paper airplane or parachute
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NC Science Olympiad
Coaches Clinic 2009
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Conclusion
• Questions?
• How can we help you prepare?
• How are you going to coach your
students for this event?
• Session evaluation
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Coaches Clinic 2009
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Questions or Comments?
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Coaches Clinic 2009
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Coaches Clinic 2009
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