Topic 3.2 - How Do Electrical Charges Behave?

The charges of electrons

Surround the nucleus; can be rubbed off a material

The charges of protons

Part of the nucleus of atoms and are held firmly in place

Charging by friction: Charging a material by rubbing

When electrons are rubbed off a material, it becomes positively charged

Material gains electrons and becomes negatively charged

If electrons rubbed off one material, the protons stay behind and the material becomes positively charged

The material that gains the electrons becomes negatively charged

Electrically charged materials have an unequal number of positive and negative charges

Different materials have different tendencies to either gain electrons or lose electrons.

If rabbit fur is rubbed with cat fur the rabbit fur will ______ electrons while the cat fur will ______ electrons. Therefore

Rabbit Fur will be _______

Cat Fur will be _________

If human hair is rubbed with a rubber balloon the human hair will ______ electrons while the balloon will ______ electrons. Therefore

Human Hair will be _______

Balloon will be _________

Opposite charges attract each other

Like charges repel each other

The law of electric charge explains why charged objects attract neutral objects

All neutral objects have an equal number of protons and electrons

Why a charged balloon sticks to an electrically neutral wall

When a charged object (balloon) is brought near a neutral object (wall), the electrons in the neutral object do not come off

Negative charges in the wall are pushed away from the surface by the negative charges on the balloon

Positive ends of the molecules in the wall are attracted to the negative charges on the balloon

This attraction is strong enough to hold the balloon to the wall