Charge (+) charge (proton) (-) charge(electron) 2 Types: An object becomes “charged” when it has more (+) charges than (-) charges, or more (-) charges than (+) charges !! We’ll discuss this later!!

What type of relationship do protons and electrons have?

Basic Law of Electrostatics Like charges repel Opposite charges attract

Electroscope Device used to detect electric charge. An electroscope cannot tell whether a charge is (+) or (-)!! It can only tell is that or is there not a charge!!

Net accumulation of charge “Stationary” Electricity Static Electricity Net accumulation of charge “Stationary” Electricity In terms of electricity, where have you heard the word “Static”?

“Help, I can’t get my hair to stay down!!!!!!” What in the world could cause this dog’s hair to stand up like it is?

Static Cling

Click “That guy”!

What makes an object “charged”? Objects become “charged” when they gain or lose electrons. If electrons are gained, object becomes (-) charged. If electrons are lost, object becomes (+) charged. NOTICE: Electrons move, Protons do not move!!

3 ways to charge an object: Conduction Friction Induction

Person is wearing leather soled shoes which actually “lose” electrons to the carpet. If the person were wearing rubber soled shoes, the shoes would “steal“ electrons from the carpet.

You walk across a neutral carpet covered floor You walk across a neutral carpet covered floor. As your feet rub across the carpet, you pick up electrons!!

Look at all the new electrons you have on your feet!!!

“Do charged objects have to be touching in order to have an affect on each other?”

Electric Field The area surrounding a charge where the affects of the charge can be felt.

Strength of the electric field Strength is dependent on 2 things: Size of the charge—the greater the difference in + and -, the larger the charge. Distance from the charge—the further you get from the charge, the lesser the strength.

Conductors vs. Insulators Conductor—a material that allows electrons to flow easily through it. Insulator—a material that does not allow electrons to flow through it.

Notice that in a conductor, the electrons are free to move around Notice that in a conductor, the electrons are free to move around. They are not “confined” just around the protons. Therefore, electricity can move through them.

In an insulator, the electrons are not free to move from place to place. They are generally confined to moving only around the atom they are attached to. Therefore, electricity cannot move through them.

Note-Taking Skills Wst. Section 1 Electric Charge Protons have positive electric charge. Electrons have negative electric charge. In most atoms, the charges of the protons and electrons cancel each other out and the atom has no charge. Atoms become charged by gaining or losing electrons. Static Electricity- the accumulation of excess electrons on an object!

B. Electrically charged objects obey the following rules: 1 B. Electrically charged objects obey the following rules: 1. Law of Conservation of Charge—charge may be transferred from object to object, but it cannot be created or destroyed! 2. Opposite charges attract and like charges repel. 3. Charges can act on each other even at a distance, because any charge placed in an electric field will be pushed or pulled by the field.

4. Electrons move more easily through conductors, like metals. 5 4. Electrons move more easily through conductors, like metals. 5. Electrons do not move easily through nonmetals, such as plastic, wood, rubber and glass.

Transferring electric charge 1. Charging by Contact(or Friction) a. The process of transferring charge by touching or rubbing. b. Example: static electricity from your feet charge the carpet. Charging by Induction The rearrangement of electrons on a neutral object caused by a nearby charged object. Example: a negatively charged balloon near your sleeve causes an area of your sleeve to become positively charged!

Static Discharge A transfer of charge through the space between objects because of the buildup of static electricity. Example: Lightning Grounding—Using a conductor to direct an electric charge into the ground. The presence of electric charges can be detected by an electroscope!