Constructing Ideas in Physical Science

1
Constructing Ideas in Physical Science
CIPS Institute for Middle School Science Teachers

• Joan Abdallah , AAAS
• Darcy Hampton, DCPS
• Davina Pruitt-Mentle, University of Maryland

2
Session 2 Debriefing

• What do you remember from yesterdays session (no
  peeking at text or notes)?
• What were the essential questions being
  asked/explored?
• What conclusions did we decide?
• What was/were the underlying concepts/content
  that the activities were after?

3
Deeper Questions

• What deeper questions could you envision students
  asking?
• What misconceptions or misinterpretations can you
  foresee?
• How or what would you say?

4
Deeper Questions or Possible Misinterpretations

• What is a magnet?
• What makes something a magnet?
• How can you magnetize something?
• How does something loose being a magnet?

What would you say?
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Whats a Magnet? Magnets do the following
things

• Attract certain materials - such as iron, nickel,
  cobalt, certain steels and other alloys
• Exert an attractive or repulsive force on other
  magnets
• Have an effect on electrical conductors when the
  magnet and conductor are moving in relation to
  each other
• Have an effect on the path taken by electrically
  charged particles traveling in free space.

The Magnet Library http//www.magnet4u.com/eng/new
_lib/lib_1.htm
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Why does a Magnet Work?

• Iron, Cobalt, and Nickel (and some other
  elements), as well as some alloys are
  ferromagnetic
• These materials exhibit a property called long
  range ordering
• This is a quantum effect beyond the scope of a
  middle (or high) school class
• Unpaired electrons in the material tend to line
  up
• Electrons which line up cause the magnetic effect

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Iron Fe 26
8
Cobalt Co 27
From Web Elements
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So Why isnt all Iron Magnetic?

• Usually, due to random effects, this electron
  spin alignment is limited to regions
• This randomness leads to no net magnetic field

Electrons in different directions
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How do we make it a magnet?Add an Electric Coil

• Wire coils with electricity through them create a
  magnetic field which runs through the center
• This tends to align the domains (of lined up
  electrons) in the same direction
• The greater the current, the greater the magnetic
  field
• Iron (or other ferromagnetic elements) tends to
  amplify the magnetic field

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Now it stays magnetic after we remove the wires

• The electric field makes the domains line up
• When you remove the coil, the domains tend to
  stay aligned
• This property is called hysteresis

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Earths Magnetic Field
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Want To Learn More?

• What Makes Earth a Magnetic Force?
• Magnets and Electromagnets
• Electricity and magnet playwiths
• Magnetic Expressions
• Ohio States Virtual Demo Lab (also scroll to end
  for list of other online simulation sites)

14
Can We Apply What We Learned Yesterday?Class
Activity

• Battery Power
• WHICH TILE CLEANER REMOVES SOAP SCUM THE BEST
• The Science of Water
• What Can Affect Ones Perception of Sound
• Why does junior tennis have such a high injury
  rate?

Judge these using the rubric provided
15
More Fun

• A Science Fair How Not to Guide
• http//www.wcsscience.com/scienceexperiment/guide.
  html
•  Montykins
• http//www.montykins.com/mkins/000620.html
•  Bogus Entries are Fair Game
• http//www.gsdsef.org/pdfs/mar30Article01.pdf