Electric charge is a fundamental property of matter, like mass. Electric charge is a fundamental property of matter, like mass. Objects are either positive, negative, or neutral. Objects are either positive, negative, or neutral. Like charges repel, opposite charges attract. Like charges repel, opposite charges attract.

Charges come from within the atom. Charges come from within the atom. – Protons = positive – Electrons = negative Electric charges depends on an imbalance of protons and electrons Electric charges depends on an imbalance of protons and electrons

p – e = charge (# of p + – # e - = net charge)

The unit of electric charge is the coulomb (C). The unit of electric charge is the coulomb (C). – Charge for both p + and e - = 1.6 x C

Electrical forces cause electrons to move, or flow. Electrical forces cause electrons to move, or flow. – Electricity is flowing electrons. Conductors allow electricity to flow. Conductors allow electricity to flow. – Metals tend to be excellent conductors. Insulators resist the flow of electricity. Insulators resist the flow of electricity.

Objects can be charged by: Objects can be charged by: 1.Friction o Moving an object against another can transfer electrons from one to the other o Example: rubbing balloon on your hair. 2.Contact

Objects can be charged by: Objects can be charged by: 1.Friction 2.Contact o Touching a charged object to an uncharged object can transfer electrons. o Example: Shock from touching door knob after rubbing feet on carpet.

Objects can be charged by: Objects can be charged by: 1.Friction 2.Contact 3.Induction o As a charge object approaches an uncharged object, it will push like charges away and attract opposite charges.

The force that attracts or repels electric charges is electric force. The force that attracts or repels electric charges is electric force. Electric force depends on charge and distance Electric force depends on charge and distance – The greater the difference in charges, the stronger the force. – The greater the distance between charges the weaker the force.

Electric force acts through a field Electric force acts through a field – Electric field – the space around an electric charge that is affected by it. – Often shown by drawing electric field lines that point in the direction a positive charge would move. – Electric field lines never cross one another.