Electric Charge, Electrification and the Electric Field
Why a comb picks up bits of paper, why you feel a spark on a dry winter day, and what fills the space around every charged body.
Big Idea: Rub two different materials together and one of them steals tiny particles — electrons — from the other. The body that loses electrons becomes positively charged, the one that gains them becomes negatively charged. Around every charged body there is an invisible electric field that pushes and pulls on other charges without touching them.
By the end of this topic you will be able to:
- explain what electrification is and how rubbing charges a body,
- name the two kinds of charge and state the rule "like charges repel, unlike charges attract",
- use the structure of the atom to explain where charge comes from,
- tell a conductor from an insulator,
- describe the electric field and draw its field lines,
- explain how an electroscope detects charge,
- count electrons using the elementary charge e.