Day 62 Topic 7: Charges and Circuits. Mini Lab…BoC…and next class.
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Transcript of Day 62 Topic 7: Charges and Circuits. Mini Lab…BoC…and next class.
Day 62Topic 7: Charges and Circuits
Mini Lab…BoC…and next class
3rd Quarter5 Full Classes of Topic 7
Q3 Review Day 67 3/25, 3/26
Q3 Exam Day 67 3/27, 3/30
Brunch of Champions Day 68 3/31, 4/1
half day on 4/2? Yeah right; don’t show up because I am not going to be doing important physics that day.
Topic 7: Charges and CircuitsToday: Review of charges,
discussion of basic atomic physics, electric forces.
Leaving here today: Lots of atomic stuff:How charges are quantizedRules of charge interactionsCharge Separation
1st Thing To DoMake a list of all things you know/remember/can deduce about a) the makeup of an atom
b) how the atom and parts act/react in nature
Quick Review:Parts of atom:
How do they interact?
What is Charge?No idea. It’s a property…
Positive or Negative
ProtonsNeutronElectrons
A fundamentalA fundamental charge is:
Charge is a CONSERVED property, which means…
If Neutral…Are there protons or electrons in
the atom/object?
A non-neutral object is Ionized (or an Ion).
Basic Charge RulesLike Charges_____________
Opposite charges_____________
So in the nucleusTell a story of how
the charges wantto move in thenucleus…
There is a gravitational attraction (from the mass property…tiny) that keeps the nucleus together
There is an electrical repulsion (from the charge property…large) that wants to separate the nucleus
There is a Strong Nuclear Force (from the quarks and…., huge) that keeps the nucleus together
Tape It Up!Each group follow my tape
instructions carefully… Label them A (top) and B (bottom)
Explain the charges of A, B and system before and after the ripping. Be detailed, be dramatic.
How do the signs of A and B compare?Before After
How does the amount of charge of A and B compare?Before After
Has the amount of mass and/or the elemental property of A and B changed?
Tape It Up!How do the signs of A and B compare?
Before AfterHow does the amount of charge of A
and B compare?Before After
Charge of system compared to each tape and total, signs, have you changed the physical properties (mass, element) of the tape?
Picture… Drawing TapeLets draw pics before and after,
and use the SNF to describe what was exchanged
Major IdeaThe net charge on each object (Q) is
measured in Coulumbs (c).
Ex: Tape A had a charge of ___________
Those charges felt charges on the tape, and created a net electrical force between them.
This Coulumb Force is the Electric Force FE. Can attract or repel
WaterWatch for a bit
Why did the water attract to both + and -?
POLAR!
The molecule rotated to the attractive part was closer to the rod, and thus had a stronger attraction than the further repulsion.
Now get fur and rod and canCharge up the rod using the furry
part (fluffier is better).
Don’t touch can, bring it close and parallel to the side.
Observe…
Can drawing and Rod…before
Can drawing and Rod…After
Summarize