1Charges in everything
Everything is made of atoms, which contain positive protons and negative electrons. Usually there are equal numbers, so an object is neutral.
protonelectronneutral
Lesson 6.4 notes
Static electricity
Charging by rubbing, attraction and repulsion between charges, electric fields and sparks.
2Charging by rubbing
Rubbing two materials together can move electrons from one to the other. Only the electrons move: the protons stay where they are.
3Gain or lose
The object that gains electrons becomes negatively charged. The object that loses electrons is left positively charged.
negatively chargedpositively charged
4Like charges repel
Objects with the same charge, both positive or both negative, push each other apart: they repel.
repel
5Opposite charges attract
Opposite charges pull towards each other: they attract. The closer the charged objects are, the bigger the force.
attract
6Electric fields
A charged object has an electric field around it: a region where other charges feel a force without touching. The field is strongest close to the object.
electric field
7Sparks and lightning
When enough charge builds up, it can jump across a gap as a spark. Lightning is a giant spark between a charged cloud and the ground.
spark
Explore: Charge lab
Choose the charge on two balloons and how far apart they are. See whether they attract or repel, and how big the forces are.
Common mistake: Only electrons move when things are rubbed
Rubbing moves negative electrons from one object to the other. An object becomes positive by losing electrons, not by gaining positive charge.
Remember
- Rubbing two materials together can move electrons from one to the other. Only the electrons move.
- Gaining electrons makes an object negative; losing electrons leaves it positive.
- Like charges repel and opposite charges attract without touching: an electric field acts across the gap.
Going further at GCSE