Notes 8: Electric Charge Chapter 7 Section 1 Page 192

Review of the Atom Earlier this year we learned about the atom. The atom is comprised of three components: Protons (located in the nucleus) Neutrons (located in the nucleus) Electrons (located outside the nucleus) The PROTON has a POSITIVE charge and the ELECTRON has a NEGATIVE charge

Positive and Negative Charge If an atom has more protons than electrons, it has a positive net charge. OR If an atom has more electrons than protons, it has a negative charge.

Charges Exert an Electric Force When two charged objects are brought close to each other, they will either attract or repel each other. This is called the Electric Force. Opposites Attract. Similar Repel. https://www.youtube.com/watch?v=jkYz1WlpRSQ

Transferring Charge from Carpet <-CLICK ON THIS LINK Whenever an object is charged (meaning it has a net positive or negative charge), it is because electrons are transferred from one object to another. For example, when you rub your feet on carpet, electrons move from the carpet to your shoes. This gives you a negative charge since you have extra electrons, and the carpet a positive charge because it lost electrons. Transferring Charge from Carpet <-CLICK ON THIS LINK Law of Conservation of Charge - charge can be transferred from one object to another but cannot be created or destroyed.

Charging Objects There are two common ways to charge an object: Charging by Contact - process of transferring charge between objects by touching or rubbing. An example of this would be rubbing your feet across the carpet. Charging by induction - process of rearranging electrons on a neutral object by bringing a charged object close to it. An example of this would be a charged balloon sticking to you even though you don’t have a net charge. https://www.youtube.com/watch?v=5cILFl0tzpI <-a video on technology that using induction to wirelessly charge your cell phone

Conductors and Insulators When you touch something and it shocks you, it is because electrons are moving from your hand to the doorknob. Some objects can move electrons very easily, others prefer to hang on to their electrons. Conductor - material, such as copper wire, in which electrons can move easily. Insulator - material, such as plastic, in which electrons are not able to move easily.

https://www.youtube.com/watch?v=AM5EYO5wWMA Watch the above clip of Back to the Future. Name three objects that are used as conductors and three objects that are used as insulators in this scene.

Summary There are two types of electric charge - negative and positive. Electric charge can be transferred from an object, but it can’t be created or destroyed. Opposites attract and similar repels. A conductor allows electrons to move easily and insulator doesn’t allow electrons to transfer easily. Electric charge can be transferred two ways - contact and induction.