ELECTROSTATICS

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Electrostatics-the study of stationary charges or charges are at rest

Charging by friction -the build-up of friction as one material makes contact with and rubs against a different material

Lightning-There is friction between air and water vapour of the clouds

Law of conservation -charges are neither created nor destroyed it is merely separated or allowed to move from one object to another to equalise the charge

Triboelectric charging- when electrons are rubbed on or off by friction

NATURE OF CHARGE USING A CHARGED ELECTROSCOPE

-a charged electroscope can be used to determine the nature of the charge of the charged body

WHEN A LIKE CHARGE IS BROUGHT CLOSE TO THE DISK OF THE CHARGED ELECTROSCOPE THE LEAVES DIVERGE FURTHER

WHEN AN, UNLIKE CHARGE, IS BROUGHT CLOSE TO THE DISK OF THE CHARGED ELECTROSCOPE THE LEAVES COLLAPSE SLIGHTLY

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1. PERSPEX ROD BECOMES POSITIVELY CHARGED BY FRICTION

-During, rubbing,2 electrons are transferred from the cloth to the rod

2. A PVC BECOMES NEGATIVELY CHARGED BY FRICTION

-During rubbing,3 electrons are transferred from the rod to the cloth

CONCLUSION:

THE PERSPEX ROD LOSES ELECTRONS AND THE CLOTH GAINS ELECTRONS THERE THE PERSPEX RODE IS POSITIVELY CHARGED.

THE PVS GAINS ELECTRONS FROM THE CLOTH ONTO THE RODS AND THE CLOTH LOSES ELECTRONS MAKING THE ROD NEGATIVELY CHARGED

DISCHARGING: the flag may occur when the body with excess electrons loses its electrons to the body which has a deficiency of electrons

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THE VAN DE GRAAF GENERATOR

-TO DEMONSTRATE THE EFFECTS OF STATIC ELECTRICITY

REPULSION SPHERE

-electrons move from the metal dome onto the sphere .since both the dome and the sphere have like charges, the dome repels the sphere

HEAD OF HAIR

-electrons move from the metal dome onto the hair fibres. the dome repels the hair fibres and also repel each other causing them to stand straight.

NEON LAMP

-electrons jump from the metal dome onto the neon lamp .the movement in the neon lamp causes the lamp to flicker or glow

POINT DISHARGER NEAR HAIR

-electrons jump from the hair fibres onto the air particles and into the point discharger .The hair fibre loose excess electrons and become neautral therefore they collapse .

WHIRL

-electrons collect on the sharp point of the whirl and then jump into air particles .They become become negatively charged since air particles have like charges they repel each other creating an electric wind .This causes the whirl to rotate

ELECTROSCOPE

- object is charged or not

- to determine the nature of the charges postively or negatively charged

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CHARGING AN ELECTROSCOPE

CHARGING BY CONTACT

PVC ROD

OBSERVATION: the leaves diverge and remain diverged when the rod is removed

When the charged PVC touches the neutral electroscope it repels electrons from the disc down onto the leaves

The disc becomes positively charged while leaves are negative

The positive disc attracts electrons from the PVC rod

These electrons move from the PVC rod onto the disc, down onto the leaves

The leaves have an excess of electrons

have like charges so they repel each other and diverge

Leaves remain diverged with a permanent negative charge

CHARGING BY INDUCTION

INVESTIGATION: to charge an electroscope positively by induction, you must start with a charged negative PVC ROD

When the PVC rod repels electrons from the disc down the metal rod onto the leaves of the electroscope

The disc becomes positively charged while the leaves have a temporary negative charge since the leaves repel each other and diverge

Earthing provides a conducting path with the ground.

Excess electrons move from the leaves to the earth . The leaves are now neutral since the negative PVC rod repel electrons out of the electroscope

When the earthing finger is removed and then the PVC rod is removed

The leaves diverge with a permanent positive charge

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