Static Electricity Summary

Only two types of charge! Positive Charge (protons – therefore in nuclei of atoms ) Negative Charge (electrons – therefore orbiting atoms – and can be ‘brushed off’ onto other atoms making ions

Only electrons move… Positive Charged Object – too few electrons Negative Charged Object – too many electrons Net charge is ALWAYS due to ELECTRON transfer – protons moving about would change the elements you are dealing with.

Opposite Charges attract

…Like Charges Repel

It all depends on gravity… Whether you can see a charged object ‘react’ to another one depends on weight. Two forces are in operation – electric force and gravitational force. If the electric force is bigger the object can be seen defy gravity… or in the case of the object on the left inertia and friction !

Charging by Friction Some objects are more attractive to electrons than others. If you rub a balloon (very attractive to other atoms’ electrons) together with a woollen jumper. It will ‘steal’ some of the electrons and leave the jumper postive. The balloon will have become negatively charged by friction.

Charging by Induction If the balloon is brought near to a neutral object the charged region around it (its electric field) will affect the electrons in the neutral object. It will make them move away from it – giving the surface of the neutral object near to the balloon a positive charge. The balloon will then be attracted to it and will stick to it.