Electrostatics

Electrostatics

The branch of science dealing with static charges and their electric fields

The Greek word for amber, ήλεκτρον electron, was the source of the word 'electricity'

Static Electricity

A little history

The science of electricity has its roots in observation, known in 600 BC that a piece of amber rubbed with animal fur would attract straw, feathers

Thales of Miletos (Greece) in credited with this discovery

What is amber?

Amber is the fossilized form of tree resin…not the same as sap.

Resin is similar to our scabs. It flows out of the tree to plug a hole.

Benjamin Franklin

1752 By tying a key onto a kite string during a storm, Ben Franklin , proved that static electricity and lightning were the same.

The Leyden Jar

Progress quickened after the Leyden jar was invented in 1745

The Leyden jar stored electricity and therefore could be studied at length

The Battery

A new interest in current began with the invention of the battery. Luigi Galvani had noticed (1786) that a discharge of static electricity made a frog's leg jerk.

Galvani thought the leg supplied electricity, but Alessandro Volta thought otherwise. He showed that the metal plate and the Leyden jar were different metals and produced a current. He built the voltaic pile, an early type of battery, as proof.

A quick review of the atom

Every atom has a ______ charged nucleus surrounded by ____ charged electrons.

positively

negatively

Electrons

_______ move in and out of fixed pathways around the nucleus

Charges

Two kinds: positive and negative (terms coined by Benjamin Franklin)

Like charges ________Unlike charges ______

repel attract

Objects that tend to give up electrons and become positive:

GlassNylonFurHairWool

Be glad you are not a cat

http://www.youtube.com/watch?v=bcLDx_oiSMY

Objects that tend to attract electrons and become negative:

• Rubber• Styrofoam

Let’s review

#1Balloon on wall

Let’s review

#2Electroscope

Let’s review

#3Water and balloon

Let’s Review

#5 2 balloons held near each other

Bill Nye

http://www.youtube.com/watch?v=Z-77IzaXGcg