Demo Van de Graaff match

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• Demo- Van de Graaff- match
• Space near the Van de Graaff is altered- match is
  not blown out by air!
• What affected the flame?
• The Electric Field!

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Fields

• Field around a magnet
• Field around a black hole
• Field around a Van de Graaff
• Forces that surround a mass (gravitational field)
• All have altered space around them

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Electric Fields

• The space around every electric charge is filled
  with an electric field- a kind of aura that
  extends through space

Gravity holds the satellite in place, and
electric force holds electron in place They are
both in force fields.
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Van de Graaff

• How does the Van de Graaff work?
• Demo- answer questions on handout

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Electric Fields

• Read the handout on Fields
• Answer the questions (the guide may help you with
  some questions- others you will need construct on
  your own)

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Electric Field Lines

• Remember- these lines only represent the the
  fields!
• Where the lines are farther apart, the field is
  weaker
• For an isolated charge, the lines extend to
  infinity
• For 2 or more opposite charges, the lines go from
  the positive and terminate on a negative

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Electric Field Lines

• Think of your electric field hockey game as you
  look at the next illustrations

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How are these drawn?? Simple rules for drawing
field lines will follow
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• The photo is bits of fine thread suspended in an
  oil bath surrounded by charged conductors.
  Notice how they line up.
• Oppositely charged plates
• Equal and opposite charges
• Oppositely charged plate and cylinder
• Equal like charges

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Drawing Field Lines

• Lines begin on positive charges and end negative
  (or infinity)
• of lines draw is proportional to magnitude of
  charge (more lines means greater charge) Use
  this as a conceptual representative of the
  situation!
• No field lines can cross each other

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Field Lines

• Remember Field Lines represent electrical force
  fields.
• Is there anywhere in this diagram where there
  would be a zero net force?

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Class Assignment

• Handout on Field Lines- Visualized

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Projects

• You will begin work on your year end projects
  tomorrow.
• This handout outlines the requirements.
• You will have a sub tomorrow, and will be
  watching a video, and spending time working on
  the first assignment of your project.