The discovery of electricity is generally credited to the __

They observed electric charges and the forces between them in a variety of situations

a plastic-like substance formed by allowing the sap from certain trees to dry and harden

The Greek word for amber is__

there was no clear experimental demonstration of the existence of the electron until the late

There are two types of electric charge called __

has a positive charge

has a negative charge

is the origin of the terms electricity and electron

Like charges

unlike charges

Like charges

The terms like and unlike thus refer to the __

A charge is __

is a fundamental property of matter

the amount of charge that is "on" or "carried by" a particle determines how the particle reacts to electric and magnetic fields

it is similar to the quantity we call mass

determines how it reacts when a force

We have already noted that Coulomb's law is very similar in form to

can move in a circular orbit around a positive charge, just like a planet orbiting the Sun

is always an attractive force

can be either attractive or repulsive.

is a measure of the amount of matter it carries

is a measure of the amount of "electric-ness" it carries

are both primary entries in our dictionary of physics terms, but it is not possible to give definitions for these fundamental entries in our dictionary.

In the SI system of units, charge is measured in