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Chapter 7: Electricity Learning Target Vocabulary Word Definition Facts or Examples If a _______ (+ charge) and ___________ (- charge) come together, they will _______________. If 2 electrons come close together they will ______________. Lesson 1 I can explain how electric charges and fields interact. . . electricity the interaction between ______________ ______________ electric force the force between ___________ objects electric field I can describe how static electricity builds up and transfers . . . static electricity A region around a charged object where the object's _________ __________ is exerted on other ______________ objects. The ___________ of charges on an object. Charges build up but do not flow _________________. When you rub a balloon, it becomes ____________ charged. The electric field is __________. Electric fields and forces get ___________ the farther away they are from the charge. There are 4 methods by which charges can redistribute themselves to build up static electricity: friction, conduction, induction & polarizaton. Symbol/Picture Conservation of charge friction conduction induction polarization charges are neither ______________ or _______________ If one object loses electrons, another object must _______________________. transfer of electrons from one ____________ object to another by _____________ the objects together. The object that gains electrons becomes ________________ charged. The transfer of electrons from one object to another by ____________ contact or _______________. Electrons flow from the object that has more ____________ charge to the object that has more _________________ charge. Electrons can ____________ to the electric field without ______________ the object When a metal object is close to a negatively charged object, electrons are _____________ by the field and move _______ from it. The close end becomes ______________ charged. Electrons react to ___________ __________ resulting in individual atoms having charged __________ that are attracted to charged objects. static discharge The ___________ of static electricity as electric charges ____________ from one object to another. Static discharge often produces a ___________, which happens more in the winter because the air is dry. Ex. lightning Lesson 2 I can explain how an electric current is produced . . . I can explain how conductors are different from insulators . . . I can explain what causes current to flow and how resistance affects current . . . Current is measured in ______________ (amp or A). The number of amps describes the amount of charge flowing past a given point each ______________. electric current The continuous flow of electric charges through a __________________. electric circuit A complete _______________ path that charges can flow through. If an electric circuit is broken, charges _________________ flow. conductor A material through which charge can flow _______________. Metals, such as ____________, are good conductors because electrons can move freely. insulators ________________ allow charges to flow Example = ________________. Electrons in insulators cannot move freely among atoms. voltage The difference in ____________ energy per charge between _____________ points in a circuit. resistance Diameter & resistance The ____________ the wire, the less resistance. The measure of how _______________it is for charges to flow through an object. The ________________ the resistance, the ___________ current there is for a given voltage. Measured in ohms __ Length & resistance Material & resistance The four factors that determine the resistance are _________________, _______________, material, and ____________________. Temperature & resistance The __________ the wire, the more resistance. The shorter the wire the less resistance. Conductors like metals have _____________ resistance. Insulators like rubber and plastic have _________________ resistance. The ________________ the temperature, the more resistance. The ______________ the temp, the less resistance. Lesson 3 I can explain Ohm's Law . . . I can describe the basic features of an electric series and parallel circuits . . . Ohm's Law parts of an electric circuit series circuit Ohm found that current, _____________ and resistance in a circuit are always related in the same way. All electric circuits have devices that run on electrical energy (load), sources of electrical energy (battery/power plant) and conducting wire. A circuit with only one _____________ for the current to take. voltage ___________ = current _______ = current x resistance Energy is always ____________ in a circuit. It does not get used up. It gets ____________ into heat, ___________, mechanical and sound energy. Devices that transform are called _________________. Advantages - simple to design and build. Disadvantage - if one light goes out, they all do and the more bulbs you add, the dimmer the bulbs become because the resistance increases. parallel circuit Lesson 4 I can explain how to calculate electric power and energy use . . . power A circuit that has ______________ paths for current to take. The ___________ at which energy is transformed from one form to another. If one bulb goes out the others remain lit. If you add extra bulbs in extra branches, the resistance decreases and the brightness does not change. ________________is measured in watts (W) _________ = Voltage x Current __________ = Power / Voltage energy _______ = Power x Time Energy = watts x time 1,000 I can describe measures that help protect people from electrical shock and short circuits . . . short circuit third prong/ grounded A connection that allows current to take the path of _____________ resistance. Third prong on an electrical plug ____________ the wire by connecting it to Earth. Energy is measured in _____________________ Ex. touching a frayed wire current can flow through the person. SHOCKS can be prevented with devices that redirect current or break circuits. fuses circuit breakers Devices that _________ if they get too hot. This breaks the circuit. Switches that will bend _________ from circuits as they heat up. They can be reset. Learning Targets Chapter 7 Lesson 1 I can explain how electric charges and fields interact. . . Charges that are the same _______________________ each other. Charges that are different ___________________each other. I can describe how static electricity builds up and transfers . . . There are four methods by which charges can redistribute themselves to build up static electricity: by ___________________, by __________________________, by ______________________________, and by ______________________________. Lesson 2 I can explain how an electric current is produced . . . When electric charges are made to flow through a material, they produce an ______________________________________. I can explain how conductors are different from insulators . . . The atoms in conductors have ___________________________ bound electrons that can move ______________________. Electrons in insulators ___________________________ move freely among atoms. I can explain what causes current to flow and how resistance affects current . . . Current flow is affected by the energy of the _________________________ and the ________________________ of the objects that the charges flow through. Lesson 3 I can explain Ohm's Law . . . Ohm found that the current, _________________________, and resistance in a circuit are always ________________________ in the same way. I can describe the basic features of an electric series and parallel circuits . . . All electrical circuits have the same basic features: devices that are run by ________________________________________, ________________________________ of electrical energy, and _____________________________ wires. Lesson 4 I can explain how to calculate electric power and energy use . . . Power is calculated by multiplying _________________________________ by _______________________________. The total amount of energy used is equal to the ____________________________ of the appliance multiplied by the amount of _________________________________ the appliance is used. I can describe measures that help protect people from electrical shock and short circuits . . . Shocks can be prevented with devices that redirect current or ___________________________________________________.