# Are you positive?

 Unit Home Topic Home Chapter Home 4 Pictures 0 Animations 2 Videos Chapter Summary 0 Activities 1 Exams

## What is a charge?

A charge is an influence of energy that moves particles in a particular direction. In science, there are two charges, positive and negative. The term 'charge' refers to any particle or group of particles that have the ability to influence other particles with this energy.

## Particles

An atom is the smallest form of matter that keeps its properties. It is made up of a nucleus in the centre, which contains protons (positively charged particles) and neutrons (neutral particles). Negatively charged particles, called electrons, orbit the nucleus. The positively charged protons and the negatively charged electrons usually balance out to make the atom neutral. A neutral atom possesses no charge. Refer Image 1

## Positive and negative

Electrons, being on the outer part of an atom, are easily moved. Charge occurs because of the addition or removal of electrons. If the charges of the protons and electrons do not balance, then the atom has an overall positive or negative charge.

Any substance with more protons than electrons will have a positive charge. To become positively charged, an atom must lose electrons. We represent positively charged particles with a '+' symbol.

Alternatively, any substance with more electrons than protons will have a negative charge, which comes from the addition of electrons. We represent negatively charged particles with a '-' symbol.

Substances with unlike (opposite) charges attract (pull towards) each other, while substances with like (same) charges repel (push away from) each other. This means that positively charged particles will attract negatively charged particles and vice versa, but positive-to-positive attractions and negative-to-negative attractions do not occur. Refer Images 2,3 and 4

Unlike charges attract each other because the positively charged particles need more electrons and the negatively charged particles have too many electrons. Like charges repel because substances with the same charge have nothing to offer.

## Creating a charge

You can create a charge if you rub two neutral substances together. The energy from rubbing dislodges the electrons and makes them move easily. The electrons from one will move to another making one substance positively charged and the other negatively charged. We call this rubbing energy friction. Refer animation

Chapters:

## Pop Quiz

The more you learn - the more you earn!
Earn up to points by getting 100% in this pop quiz!

### Question 1/5

1. Which of these particles are easily added or removed to give a substance a negative or positive charge?

 neutron orbit proton electron