What is “static” electricity?Technically there’s no such thing as static (“standing still”) electricity. All electricity is dynamic (moving!)

electricity = current of moving Static = not moving electric charges

http://www.physics4kids.com/files/elec_intro.html

What people call “static electricity” is a real thing, but the name for it is an oxymoron.

Creating Charges with Friction - Triboelectricity

http://regentsprep.org/Regents/physics/phys03/atribo/default.htm

Friction between shoes and carpet causes e- to be pulled off of the carpet, and onto shoes

(or vice-versa, depending on materials.)

You gain a tiny, excess negative electric charge.

These e- are “static” (not moving) as long as they don’t go anywhere.

Now walk towards a region that’s missing e- (a positively charged region) The + region attracts your e-

e- jump from you to the other region! spark

This by definition is a flow of electrons!

So this flow of electrons is called “static electricity”

This so-called “static shock” is really a brief electric current.

It is very difficult to separate the + and - charges in any material.

Most matter has the exact same amount of + and - charges.

The total charge is 0, since the + cancels the -

This is an effect of static electric charges

No electrical current here. No spark.

Child has an excess of e- on his body.

e- repel each other

e- push each other as far apart as possible.

e- distribute themselves all over the child’s body (no direct way to see this – must look at hairs)

Hairs are lightweight. The electric repulsion is strong enough to push them away from each other.

http://www.britannica.com/eb/art/print?id=88521&articleTypeId=0

The unit of electric charge is the Coulomb (C)

Charles-Augustin de Coulomb (1736-1806)

French physicist who made the first accurate measurements of the forces between electric charges in 1783.

One C is a ginormous amount of charge, much larger than anything seen in everyday experience.

1 C = # of e- transported by a 1 ampere of current, in 1 second

1 coulomb = 6.24 × 10 18 electrons! That’s ginormous!

Put 1C of + charge one meter away from 1 C of – charge

Repulsive electrical force between them = 9,000,000,000 Newtons !

We’ll usually deal with milliCoulombs and microCoulombs (μC)

We detect charged objects with an electroscopeHas two lightweight metal leaves that normally hang down.

They attract or repel each other, depending on the charge nearby.