static and current electricity april 2006 by: brianna shields

Static and Current Electricity

April 2006

BY: BRIANNA SHIELDS

DO NOW

• 1. What type of wave is a sound wave?

• 2. Which type of wave from the electromagnetic spectrum has the least amount of energy and the longest wavelength?

• 3. Why can’t you hear a sound in outer space?

GOAL

• To differentiate between static and current electricity

Fill in the answers to the video questions while you watch the video.

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• Proton = P= (+) = nucleus

• Neutron = N = (0) = nucleus

• Electron = E = (-) = outside nucleus

Bohr Model of an Atom

8P 8N

More on subatomic particles

• Neutral atom

• Forces

• # P = # E

• 1. P-E = attract• 2. P-P = repel• 3. E-E = repel

• How do atoms become charged??

Static Electricity

• Static Electricity

• 1. The accumulation of extra negative e- on an object

• 2. Only e- can be transferred

• 3. Opposite charges attract

• 4. Like charges repel

Static Electricity

• Static Electricity Example

• 5. Extra e- = negatively charged object/atom

• 6. Missing e- = positively charged object/atom

• For each of the following static electricity examples you must do the following: – 1. Draw a picture– 2. Accompany it with an

explanation

Scenario 1: If you shuffle your feet on the carpet, then reach out to touch a metal door knob, you

receive a shock by a spark- explain why?

• Rubbing disturbs the atoms• Electrons rubbed off carpet

and onto your feet– Shoe has extra e’s

(negative chg)– Rug is missing e’s

(positive chg)– Extra electrons from the

shoe are transferred to the doorknob in the form of an electrical spark

Scenario 2: Clothing sometimes clings together upon removal from the dryer-

Why?

• Electrons rub off clothes and stick to others

• Some items get a negative charge

• These clothes are attracted to the ones with a positive charge (clothes missing electrons).

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Scenario 3: Charging by Induction- charged object and neutral object attract when atoms in neutral

object rearrange their protons and electrons

• Rub a balloon w/ a cloth to charge it, it accumulates extra negatives on it

• Bring it close to a wall and it rearranges the atoms on the wall

• It pulls protons closer and pushing electrons away

Scenario 4: Charged skotch tape

• Ripping the tape off the desk gives it a charge

• When the charged rod is brought up to the piece of tape it is either attracted or repelled

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Scenario 5: Flying Pepper

• Charging the rod with fur transfers e’s to the rod

• Neutral pepper experiences rearrangement of the e’s so the p’s on top are attracted to the pepper

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Scenario 6: Bending Water

• Charge the rod, bring it close to water

• It rearranges the electrons in the water causing them to be attracted to the negative rod

Scenario 7: Electroscope

• The negatively charged rod transfers electrons to the metal knob

• The e’s travel down the metal rod into the aluminum foil

• Each piece of foil, then has a negative charge- so they repel

Scenario 8: Lightning

• The accumulation of negative charge in clouds

• Electrons transfer to positively charged ground to even out the charge

• Produces electrical spark known as lightning

Conductors & Insulators

• Conductor

• Insulator

• 1. A material that allows e- to move easily through

• 2. Metals

• 1. A material that resists e- flow

• 2. Plastic, wood, rubber, glass

Circuits

• Current Electricity

• Creates continuous e- flow

Circuits

• Parts of a circuit

• 1. Source – Battery-pumps electrons– Flows from - to + end

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Circuits

• Parts of a circuit

• 2. Wire – Creates path for e- flow

Circuits

• Parts of a circuit

• 3. Load – Resists e- flow, converts it to

light or heat– Bulbs, toasters

Circuits

• Parts of a circuit

• 4. Switch – Opens and closes circuit path– Open circuit= no e- flow

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Examples of simple circuits

Circuit must be closed for electrons to flow……..

Circuits

• Types of circuit

• SERIES – Parts connected in a continuous

path (one loop)– A break disconnects the whole

circuit

Circuits

• Types of circuit

• Parallel – Contains various paths for e-

flow (branches)– If there’s a break, e- can take a

different path

Electricity Review Sites

• Interactive Electricity

• Mr Blobz Electricity

Circuit Drawings• 1. Draw a circuit in series

with one source, one switch and 4 loads

• 2. Draw a circuit in parallel with two wire loops, each with a load, one switch and one source

Reviewing Circuits

Reviewing Circuits

Reviewing Circuits

Reviewing Circuits

Reviewing Circuits

Draw the following circuit examples on your handout:

• Circuit in series with one source, one switch and 4 loads

• Circuit in parallel with three wire loops, one source, one switch and three loads (one on each loop).