# Electricity Law of Electric Charges Like charges repel

• Slides: 21

Electricity!

Law of Electric Charges • Like charges repel; Opposite charges attract

Using the Law of Electric Charges, predict what will happen: – A + 1. Between A & B? 2. Between B & C? 3. Between A & C? B _ C +

Electricity • Atoms have protons, neutrons, and electrons. • Same number of protons and electrons, it is balanced and neutral • Sometimes electrons get knocked out of place – free electrons (Electrically Charged) • If they go to where other electrons are missing, this creates a current of electricity!

Static Electricity! • The electric charge that builds up on an object that has gained or lost electrons. • Does not move along a wire

Static Electricity can occur in 3 ways

Charge It! v Friction Charging by friction happens when electrons are “wiped” from one object onto another. v Conduction Charging by conduction happens when electrons move from one object to another by direct contact. v Induction Charging by induction happens when charges in an uncharged metal object are rearranged without direct contact with a charged object.

Static electricity by friction 1. Friction: build up of charge by rubbing one object against another. Rubbing hair with balloon

2. Conduction: build up of charge by direct contact between 2 objects

3. Induction: build up of charge by force of attraction or repulsion WITHOUT touching one object to the other ( through open space ) Demo with Salt

http: //phet. colorado. edu/en/simulati on/balloons 2011 electricity. ppt

Current Electricity! • Electric charges are called electric current. • The flow of electric charge through a wire. • Easily controllable.

Current electricity– brain pop http: //www. brainpop. com/technology/energytechnolo gy/currentelectricity/

Examples • Light bulbs • Cars • Computers

Exit Ticket 1. What is static electricity? 2. What are three ways in which static electricity can occur? 3. What is current electricity? 4. What is an example of current electricity?