Electrostatics

1
Electrostatics

• Physics

2
A. Definition

• The study of electrical charge that can be
  collected and held in one place

3
B. Examples of Static Charge

• Socks in a dryer
• Sliding feet on carpet
• Rubbing a
• balloon

4
C. Electric states of Matter

• Neutral negative charge positive charge
• Negatively charged excess of electrons (e-)
• Positively charged deficiency of e-

5
Special Note

• e- is responsible for understanding electrical
  phenomena

6
D. Rules of Charge

• Like charges repel
• Opposite charges attract
• Charge is conserved

7
Classes of Matter A. Conductors

• Crystal
• Lattice
• e- flow
• freely

8
Conductor2. Description

• material that readily transfers charge
• e- are free to move around in the crystal lattice
  (sea of e-)

9
Conductor

• 3. Examples
• Metals
• Water
• Earth (best)
• Lightening strike Struck by lightning Roy
  Sullivan

10
B. Insulators

• 1. Description e- are tightly bound to nuclei
  and will not readily transfer
• 2. Examples plastic, wood, glass, rubber, paper

11
Semi-Conductors

• 1. e- can move more freely than in an insulator,
  but not as easily as conductors
• 2. Examples Silicon, Germanium

12
III. A. Induction

• 1. How is it done? Bring a charged object near
  another uncharged object (no contact)
• 2. What occurs? e- are either attracted or
  repelled from the charged object

13
3. Diagram
14
Induction4. Resulting Charge

• Resulting Charge
• Opposite of charging object (temporary)
• Overall charge is still neutral

15
B. Conduction

• 1. How? Touch charged object to another object
• 2. What occurs? e- are transferred

16
Conduction
17
Conduction

• 4. Resulting Charge same charge as charging
  object and charge is permanent

Video conduction and induction
18
Grounding

• Process of removing excess charge from an object
  by transfer of e- to a larger object
• Ex. middle prong on wall outlet

19

• 1. Mike is investigating the charge on several
  objects and makes the following observations C
  attracts B, D repels C, E attracts D and repels
  F, F attracts A
• If A is negatively charged and B is neutral, what
  can Michael conclude about the charge of C, D, E,
  and F?
• F is positive, E is positive, D is negative, and
  C is negative

20

• 2. A metal sphere is electrically neutral. It is
  touched by a positively charged metal rod. As a
  result, the metal sphere becomes charged
  positively. Which of the following occur during
  the process? (multiple answers)
• a. The metal sphere gains some protons.
• b. Electrons are transferred from the sphere to
  the rod.
• c. The metal sphere loses electrons.
• d. The overall charge of the system is conserved.
• e. Protons are transferred from the rod to the
  sphere.

21

• 3. A metal sphere is electrically neutral. A
  positively charged metal rod is brought very near
  to it without actually touching it. The metal
  sphere will now be attracted to the metal rod
  because..
• The metal sphere temporarily behaves as if it is
  negative.
• The metal sphere temporarily behaves as if it is
  positive.
• The metal sphere has now become permanently
  charged negative.
• The metal sphere has now become permanently
  charged positive.

22

• 4. You have built up a strong negative charge on
  your body by dragging your feet across a shaggy
  carpet. When you reach the other side of the room
  where you little brother is sitting you decide to
  touch him on the ear. You hear a satisfying
  gizzouch as he screams out in surprise. This
  electrostatic shock occurred because of
• Induction caused your brother to become
  negatively charged like you.
• Conduction cause your brother to become
  positively charge.
• Grounding caused your negative charges to travel
  through his body.

23
Extra Help

• The physics classroom
• Bill Nye the science guy