igcse-22-electriccharge

8/12/2019 igcse-22-electriccharge

1/21

EDEXCEL IGCSE / CERTIFICATE IN PHYSICS 2-2

Electric ChargeEdexcel IGCSE Physics pages 66 to 73

June 17 th 2012

Content applying to Triple Science only is shown in

red type on the next slide and is indicated onsubsequent slides by TRIPLE ONLY


2/21

Edexcel SpecificationSection 2: Electricityd) Electric chargeidentify common materials which are electrical conductors or insulators, including metalsand plastics describe experiments to investigate how insulating materials can be charged by frictionexplain that positive and negative electrostatic charges are

produced on materials by the loss and gain of electronsunderstand that there are forces of attraction between unlike charges and forces ofrepulsion between like chargesexplain electrostatic phenomena in terms of the movement ofelectronsexplain the potential dangers of electrostatic charges, eg when fuelling aircraft andtankers

explain some uses of electrostatic charges, eg in photocopiers and inkjet printers.

Red type: Triple Science Only


3/21

Electrical conductors and insulators An electrical conductor

is a material throughwhich electric currentflows easily.All metals areconductors.

Electrical insulatorshave a very highresistance to the flow of

electric current.

Complete the table below:

copper conductorrubber insulatorsteel conductormercury conductorpaper insulatorplastic insulator

diamond insulatorgraphite conductor

1

2

3

4

5

6


4/21

Electric chargeElectric charge can be either

positive or negative .

In an atom an electron has anegative charge that is of the

same size as the positivecharge of a proton.Neutrons have no electriccharge.

As an atom has the samenumber of electrons as protonsit is uncharged.

TRIPLE ONLY


5/21

Static and current electricityStatic electricity describes the situationwhen electric charges remain stationary .This occurs best with insulators.

An electric current occurs when electriccharges are moving from one place toanother.This occurs best with conductors.

TRIPLE ONLY


6/21

Charging materials using frictionWhen certain insulating materials are rubbed against each

other they become electrically charged.Electrons are rubbed off one material onto the other.The material that gains electrons becomes negativelycharged. The material that loses electrons is left with an equalpositive charge .

TRIPLE ONLY


7/21

Force and chargeWhen a charged object is brought close to anuncharged one the two objects attract each other.

The charged combattracts the column of

water

Charged balloonattracted to a wall

TRIPLE ONLY


8/21

Attraction and repulsion

Two bodies that carry different types of charge attract .

Two bodies that carry the same type of charge repel .

The law of charges:

LIKE CHARGES REPEL ,UNLIKE ATTRACT .This boys hair has all the

same type of charge!

TRIPLE ONLY


9/21

TRIPLE ONLY


10/21

Choose appropriate words to fill in the gaps below:

Static electricity occurs when electric ________ remains

____________ on an object.An __________ object can be charged by __________ it withanother insulator. One of them gains ________ and becomesnegatively charged. The other becomes equally __________

charged.The law of charges states that; like charges _______, unlike

_________.

insulatingattract repel

positively charge

stationaryelectrons

WORD SELECTION:

rubbing

insulating

attract

repel

positively

charge

stationary

electrons

rubbing

TRIPLE ONLY


11/21

Hazards of static electricityThe main danger of staticelectricity is in situationswhere a spark can cause afire or an explosion.

The Buncefield oil depotexplosion (opposite) inDecember 2005 wasthought to have been

caused by a spark.

TRIPLE ONLY


12/21

Fuel pipe problemsWhen oil or petrol ispumped along pipes astatic charge can buildup on the pipe whichcould result in a spark.

This could cause anexplosion when the fuelvapour reacts withoxygen in the air.

fuel pipe connected to earth

TRIPLE ONLY


13/21

Antistatic floorsIn operating theatres it isimportant that the doctors todo not become staticallycharged when walkingaround.

This is because some of theanaesthetic gases used areexplosive.

Antistatic material is usedfor the floor surface so thatany charge is conducted toearth.

TRIPLE ONLY


14/21

Uses of static electricity:1. Paint spraying

The spray nozzle is connected isconnected to the positive terminal ofan electrostatic generator.

As the paint droplets leave theyrepel each other and spread out toform a fine cloud of paint.

The metal panel to be painted isconnected to the negative terminal.

The negatively charged metal panelattracts the positively charged paint.

TRIPLE ONLY


15/21

2. Ink-jet Printer

Spots of ink are given an electriccharge as they leave the ink nozzle.

The deflecting plates cause thedrops to hit the right part of thepaper.

The charges on the deflectingplates change many times persecond so that each drop hits thepaper in a different position.

TRIPLE ONLY


16/21

3. PhotocopierTRIPLE ONLY


17/21

TRIPLE ONLY


18/21

4. Smoke precipitator

An electrostatic precipitator is usedto prevent the dust and ash

produced by coal fired powerstations from entering theatmosphere.

The ash and dust becomes chargedas it passes through the chargedgrid of wires.

The ash and dust is then attracted tothe oppositely charged metal plates.

When the plates are shaken the

accumulated ash and dust fallsdown to be collected and removed.

TRIPLE ONLY


19/21

Online SimulationsBalloons & Static Electricity - PhET -Why does a balloon stick to yoursweater? Rub a balloon on a sweater,then let go of the balloon and it fliesover and sticks to the sweater. Viewthe charges in the sweater, balloons,and the wall.Electric & Magnetic Forces - 'WhysGuy' Video Clip (3:30mins) - ShowsCharged Balloon & Effect of a magneton a TV screen.John Travoltage - PhET - Makesparks fly with John Travoltage.Wiggle Johnnie's foot and he picks upcharges from the carpet. Bring hishand close to the door knob and get

rid of the excess charge.

Fuel Ignition While Refuelling A Car -Word document with embedded videoclipCharged Rod & Pith Ball - IonaElectric Force Tutorial - Science TrekHow photocopying works - Universityof DelawareBBC KS3 Bitesize Revision:

Electrical Charge BBC AQA GCSE Bitesize Revision:

Attraction & Repulsion Uses of static electricity Charge, current, energy and timerelationships

TRIPLE ONLY
http://phet.colorado.edu/new/simulations/sims.php?sim=Balloons_and_Static_Electricityhttp://web.hep.uiuc.edu/home/MATS/WCIA/wcia_030205_1.wmvhttp://phet.colorado.edu/new/simulations/sims.php?sim=John_Travoltagehttp://www.ktaggart.co.uk/physics/Simulations/FuelIgnitionWhileRefuellingACar.dochttp://departments.weber.edu/physics/amiri/director/dcrfiles/electricity/pithBallS.dcrhttp://www.colorado.edu/physics/2000/waves_particles/wavpart2.htmlhttp://www.physics.udel.edu/~watson/scen103/less-copier.htmlhttp://www.bbc.co.uk/schools/ks3bitesize/science/energy_electricity_forces/electric_current_voltage/revise2.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/staticelectrev1.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/staticelectrev2.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/mainselectrev6.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/mainselectrev6.shtmlhttp://phet.colorado.edu/new/simulations/sims.php?sim=The_Greenhouse_Effecthttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/mainselectrev6.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/mainselectrev6.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/staticelectrev2.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/staticelectrev1.shtmlhttp://www.bbc.co.uk/schools/ks3bitesize/science/energy_electricity_forces/electric_current_voltage/revise2.shtmlhttp://www.physics.udel.edu/~watson/scen103/less-copier.htmlhttp://www.physics.udel.edu/~watson/scen103/less-copier.htmlhttp://www.colorado.edu/physics/2000/waves_particles/wavpart2.htmlhttp://www.colorado.edu/physics/2000/waves_particles/wavpart2.htmlhttp://departments.weber.edu/physics/amiri/director/dcrfiles/electricity/pithBallS.dcrhttp://departments.weber.edu/physics/amiri/director/dcrfiles/electricity/pithBallS.dcrhttp://www.ktaggart.co.uk/physics/Simulations/FuelIgnitionWhileRefuellingACar.dochttp://www.ktaggart.co.uk/physics/Simulations/FuelIgnitionWhileRefuellingACar.dochttp://phet.colorado.edu/new/simulations/sims.php?sim=John_Travoltagehttp://phet.colorado.edu/new/simulations/sims.php?sim=John_Travoltagehttp://web.hep.uiuc.edu/home/MATS/WCIA/wcia_030205_1.wmvhttp://web.hep.uiuc.edu/home/MATS/WCIA/wcia_030205_1.wmvhttp://phet.colorado.edu/new/simulations/sims.php?sim=Balloons_and_Static_Electricity


20/21

Electric ChargeNotes questions from pages 66 to 73

1. Explain how a material can become charged using friction(see pages 66 & 67).

2. Describe a simple experiment to show that like charges repeland unlike charges attract (see page 67).

3. Explain with the aid of diagrams how the following devicesmake use of static electricity: (a) paint sprayers; (b) ink-jetprinters; (c) photocopiers (see pages 70 & 71).

4. Describe some of the problems caused by static electricity(see page 72).

5. A ns w er th e q ues tio ns on pag e 73.6. Ver if y th at y ou c an d o al l o f th e i tem s l is t ed in t h e en d o f

chapter check l is t on p age 73.

TRIPLE ONLY


21/21

Online SimulationsBalloons & Static Electricity - PhET - Why does a balloon stick to your sweater? Rub aballoon on a sweater, then let go of the balloon and it flies over and sticks to the

sweater. View the charges in the sweater, balloons, and the wall.Electric & Magnetic Forces - 'Whys Guy' Video Clip (3:30mins) - Shows ChargedBalloon & Effect of a magnet on a TV screen.John Travoltage - PhET - Make sparks fly with John Travoltage. Wiggle Johnnie's footand he picks up charges from the carpet. Bring his hand close to the door knob and getrid of the excess charge.Fuel Ignition While Refuelling A Car - Word document with embedded video clipCharged Rod & Pith Ball - IonaElectric Force Tutorial - Science TrekHow photocopying works - University of DelawareBBC KS3 Bitesize Revision:Electrical Charge BBC AQA GCSE Bitesize Revision:

Attraction & Repulsion

Uses of static electricity Charge, current, energy and time relationships
http://phet.colorado.edu/new/simulations/sims.php?sim=Balloons_and_Static_Electricityhttp://web.hep.uiuc.edu/home/MATS/WCIA/wcia_030205_1.wmvhttp://phet.colorado.edu/new/simulations/sims.php?sim=John_Travoltagehttp://www.ktaggart.co.uk/physics/Simulations/FuelIgnitionWhileRefuellingACar.dochttp://departments.weber.edu/physics/amiri/director/dcrfiles/electricity/pithBallS.dcrhttp://www.colorado.edu/physics/2000/waves_particles/wavpart2.htmlhttp://www.physics.udel.edu/~watson/scen103/less-copier.htmlhttp://www.bbc.co.uk/schools/ks3bitesize/science/energy_electricity_forces/electric_current_voltage/revise2.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/staticelectrev1.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/staticelectrev2.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/mainselectrev6.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/mainselectrev6.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/staticelectrev2.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/electricity/staticelectrev1.shtmlhttp://www.bbc.co.uk/schools/ks3bitesize/science/energy_electricity_forces/electric_current_voltage/revise2.shtmlhttp://www.physics.udel.edu/~watson/scen103/less-copier.htmlhttp://www.colorado.edu/physics/2000/waves_particles/wavpart2.htmlhttp://departments.weber.edu/physics/amiri/director/dcrfiles/electricity/pithBallS.dcrhttp://www.ktaggart.co.uk/physics/Simulations/FuelIgnitionWhileRefuellingACar.dochttp://phet.colorado.edu/new/simulations/sims.php?sim=John_Travoltagehttp://web.hep.uiuc.edu/home/MATS/WCIA/wcia_030205_1.wmvhttp://phet.colorado.edu/new/simulations/sims.php?sim=Balloons_and_Static_Electricity

Documents

igcse-22-electriccharge