Electricity

Electron: negatively charged fundamental particle Recall Electron: negatively charged fundamental particle Proton: positively charged fundamental particle Static electricity: build up of charge Electricity: flow of electrons

Electrons and the Greeks The ancient Greeks noticed that rubbing amber could cause it to attract bits of straw The name we use for this type of attraction, electricity, comes from the Greek word for amber, electron

Key concepts about charge There are two electrical charges: –and+ Electrons have a - charge and are free to move in and between certain types of materials Protons have a + charge and cannot move The flow of electrons is called electricity

Most objects are neutral, because they have an equal number of + and – charges/electrons When 2 neutral objects are rubbed together they each get an opposite charge

The Law of Electric Charges says that opposite charges attract, like charges repel + and – charged objects also attract most neutral objects

Attract: cling together Repel: push apart Amber: yellow-orange fossilized tree resin - often containing insects

? Attraction What is the charge on the mystery box? The object could be neutral or positive

? Attraction What is the charge on the mystery box? The object could be neutral or negative

Repulsion ? What is the charge on the mystery box? It MUST be positive

Repulsion ? What is the charge on the mystery box? It MUST be negative

+ What is the charge on the pith ball? What happens when we bring a charged rod near?

Electroscopes A device that can detect the charge on an object Examples: Metal Leaf Electroscope

Your Turn Read and make a small note on Page 471 page 470 on Electrostatic Paint Sprayers Page 471 Q: 4-7