VAN DE VAN DE GRAFF GRAFF GeneratorGenerator

By By GaryGary Zhong Zhong

What is an ATOM?What is an ATOM?

What is an atom made of?What is an atom made of?

1. Protons: positive charge1. Protons: positive charge

2. Electrons: negative charge2. Electrons: negative charge

3. Neutrons: no charge3. Neutrons: no charge

Bohr ModelBohr Model

““Like charges repel, Opposite Like charges repel, Opposite charges attract”charges attract”

InsulatorsInsulators

ConductorsConductors

Static ElectricityStatic Electricity

Visible attractionVisible attraction

RepulsionRepulsion

Electrical sparksElectrical sparks

TRIBOELECTRIC SERIESTRIBOELECTRIC SERIES

HandHand GlassGlass HairHair NylonNylon WoolWool FurFur SilkSilk PaperPaper CottonCotton Hard rubberHard rubber PolyesterPolyester Polyvinylchloride plasticPolyvinylchloride plastic

Glass rod and Silk cloth demoGlass rod and Silk cloth demo

This chargeThis charge

imbalanceimbalance

is the origin of is the origin of

““Static Static Electricity”Electricity”

Hair and comb demoHair and comb demo

Combing your hair moves electrons from Combing your hair moves electrons from your hair to the combyour hair to the comb

The comb will now have an electric static The comb will now have an electric static chargecharge

Coulomb’s LawCoulomb’s Law

What is a Van de Graff Generator?What is a Van de Graff Generator?

The basic fundamental principle behind thisThe basic fundamental principle behind this

apparatus is separating opposite charges atapparatus is separating opposite charges at

both ends of the rubber beltboth ends of the rubber belt

Main apparatusMain apparatus

I.I. MotorMotor

II.II. Upper and lower Upper and lower roller roller

III.III. BeltBelt

IV.IV. Upper and lower Upper and lower brush brush

V.V. Metal sphereMetal sphere

How it works!How it works!

As the belt keeps running, more charges As the belt keeps running, more charges are deposited on both pulleysare deposited on both pulleys

Zoom in on our hairZoom in on our hair

Hair raising demoHair raising demo

Electric spark demoElectric spark demo

Factors that affect spark productionFactors that affect spark production

1)1) Materials involvedMaterials involved

2)2) Surface area Surface area connecting the connecting the materialsmaterials

3)3) HumidityHumidity

Has anyone felt a shock on dry Has anyone felt a shock on dry winter days? winter days?

Static electricity can build up in ourStatic electricity can build up in our

bodies and cause a spark to jump frombodies and cause a spark to jump from

our bodies to pieces of metal or thoseour bodies to pieces of metal or those

in our surroundingsin our surroundings

Thank YouThank You