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Electrical charge and static electricity Atoms are made of charges, protons (+) and electrons (-). These charges exert forces. They push (repel) and pull (attract)). Law of electrical charges: like charges repel (push apart) and unlike charges attract (pull toward each other). http: //www. youtube. com/watch? v=Y 5 Lxw. ZCf. W 4
Electric field is the location around ONE charge that would affect another charge within it. Electric force is the push or pull between two charges. The amount of the force is based on the size of the charges and the distance.
(1) ATTRACT OR (2) REPEL a. Two positive charges b. Two negative charges c. A negative and a positive charge d. + e. + + f. -
Charge it! Atoms usually are neutral (no charge) because they have an equal number of protons and electrons which cancel each other out. However, atoms can lose electrons and become positively charged. (Only electrons move, not protons or neutrons)
a. b. c. d. e. Electric field Electric force Neutral charge Positive charge Negative charge 3 2. 1 5. 4
How to charge an object There are three ways to charge an object. 1) Friction – rubbing two things together results in electrons moving from one object to the other. 2) Conduction – transfer of electrons by touch (similar to thermal conduction) 3) Induction – a negatively charged object approaches a neutral object making all the negative particles push away http: //phet. colorado. edu/simulations/sims. php? sim=Balloons_and_St atic_Electricity
How do we know something is charged? An electroscope shows whether something is charged by drawing the same charges from the metal and making the metal leaves spread apart.
(1) Conduction (2) Friction (3) Induction A Charging an object by rubbing it against another object so that electrons move from one to the other C B Charging an object by touching to another object so that electrons transfer. Bringing a charged object near an uncharged object so that the like charges are repelled and the uncharged object becomes charged.
(1) Conduction (2) Friction (3) Induction A B C
Moving charges Some materials conduct electricity meaning they allow charges to move easily through them, these are called conductors. - Conductors are used for wires. - Water is a conductor (unless it is distilled) - We also have to guard against materials that will allow electricity to flow through them if it isn’t something we want.
Insulators are materials in which charges cannot easily move. Such as: - Plastic - Rubber - Wood - Glass - Air
(1) Conductor or (2) Insulator 1) 2) 3) 4) 5) 6) 7) Plastic water bottle Metal hinge Basketball Lead Stapler Wooden pencil Paper airplane
(1) Conductor or (2) Insulator A B c D E
Static Electricity Static electricity is the buildup of charges on an object. It is called static because it is not moving. Electric discharge – eventually static electricity leaves an object. We call this electric discharge. It can occur slowly or quickly, as in electrical shock. http: //phet. colorado. edu/simulations/sims. php? sim=John_Trav oltage
A cell is a device that produces an electric current by converting chemical energy into electrical energy. A battery is made of several cells. Batteries use DC or direct current which moves in one direction.
Photocells is the part of a solar panel that converts light into electrical energy.
A. B. C. D. Static electricity Electrical discharge Cell Photocell 1. Converts chemical energy into electrical energy 2. Electric shock- when charges leave one object for another less charged object 3. The build up of charges on an object 4. Converts light energy into electrical energy
Electric current Current is the rate at which charges pass a certain point. Our homes use AC or alternating current where the charges continually switch from one direction to the other. Voltage may vary. In the US we use 120 V
Resistance is the opposition to the flow of electrical charge. It is a type of “electrical friction“. RESULTS IN HEAT!
A. Electric current B. Static electricity C. Resistance 1. The result when charges build up but do not move. 2. The result when charges are opposed (slow down) 3. The result when charges move pass a certain point