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## Electricity and Magnetism Flip Chart Set

### Physical Science - Middle School

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\|xiFFIFGy00538pzY Copyright © NewPath Learning. All rights reserved. www.newpathlearning.com 34-6930 Charts Charts Electricity & Magnetism Electricity & Magnetism Sturdy, Free-Standing Design, Perfect for Learning Centers! Reverse Side Features Questions, Labeling Exercises, Vocabulary Review & more!
Introduction to Electricity © Copyright NewPath Learning. All Rights Reserved. 94-4487 Visit www.newpathlearning.com for Online Learning Resources. Atoms & Elec tric Charges Atoms are made up of protons, neutrons and electrons. Protons are positively charged and electrons are negatively charged. Neutrons are not charged particles. repelled attracted Other materials, like plastic, are known as insulators, because their electrons will not easily move. Interaction of Charged Particles The interaction of electric charges is called electricity. If particles have opposite electric charges, they attract each other. If particles have similar charges, they repel each other. These interactions explain why an atom is held together. The positively charged protons in the nucleus exert a strong attraction for the negatively charged electrons that surround the nucleus. Electric Fields The attraction or repulsion that exists between charged particles is known as electric force. The area around a charged particle, where an electric force is exerted, is called an electric field. For a negatively charged particle, electric force lines are drawn pointing inward toward the particle. For a positively charged particle, the lines are drawn outward. The lines on the diagram are close together right next to the particle, where the field is the strongest. Multiple Charged Particles When two charged particles come close together, their electric fields are combined. The diagram on the left represents the electric fields of particles that are attracted. The diagram on the right shows the electric fields of particles that are repelled. The Movement of Electric Charges Objects do not normally have a positive or negative charge. However, within the atoms of some materials, the electrons are able to leave and move to other atoms. When an object gains or loses electrons, the object can become charged. Some materials, like copper and aluminum, are called conductors because their electrons can easily move. conductors insulators conductors insulators When the electrons have moved, the balloon becomes charged. Oxygen atom electron proton neutron nucleus + + + + + attracted repelled positive field negative field positive electric eld negative electric eld + positive electric eld negative electric eld + + + + + + + + + + + + + + + + + + + + +
Pause and Review Look for examples of things around your house and school that are conductors and insulators. List them below. Introduction to Electricity Conductors Insulators © Copyright NewPath Learning. All Rights Reserved. 94-4487 Visit www.newpathlearning.com for Online Learning Resources. ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________
There are several ways that an object can become charged, and electrons can be transferred. Friction is the transfer of electrons between two uncharged objects that are rubbing against each other. Induction is the movement of electrons within an object in response to an electric field of a charged object nearby. The electrons’ movement creates a charge in a certain area of the object. Static Electricity Static electricity occurs when electric charges build up on an object, but the electrons do not flow. Static electricity is what causes lightning. An excess of positive charges builds up on the ground while a large number of negative charges builds up in the clouds. At a certain point, the difference between the negatively charged cloud and the positively charged ground is so great that the static electricity turns into an electrical current. The bolt of lightning is actually a discharge of electrons traveling at the speed of light toward the positive charges. Electroscope An electroscope is an instrument used to detect charged particles. It has a long metal rod with a knob on top and two metal leaves attached to the bottom. The leaves hang straight down if the electroscope has no charge. If a charged object touches the knob and electrons are transferred, the metal leaves become charged. Because the leaves are the same charge, they repel each other and spread apart. The leaves will move in the presence of a negative or positive charge. Conduction is the transfer of charges when a charged object is in direct contact with another object. friction + + + + + + + conduction ++ + + + + induction metal rod metal leaves knob negatively charged metal rod metal rod metal leaves knob + + + + + + + + + + + knob positively charged glass rod metal rod metal leaves metal rod metal leaves knob negatively charged metal rod metal rod metal leaves knob + + + + + + + + + + + knob positively charged glass rod metal rod metal leaves How Objects Become Charged © Copyright NewPath Learning. All Rights Reserved. 94-4488 Visit www.newpathlearning.com for Online Learning Resources. In the 1700s, Benjamin Franklin studied lightning and electricity. He invented the lightning rod to protect buildings during storms. electroscope
How Objects Become Charged Pause and Review Add pluses (+) and minuses (-) to the pictures below to represent the presence of positive and negative charges. © Copyright NewPath Learning. All Rights Reserved. 94-4488 Visit www.newpathlearning.com for Online Learning Resources. Describe and illustrate: Friction ___________________________________ ___________________________________ ___________________________________ ___________________________________ Conduction ___________________________________ ___________________________________ ___________________________________ ___________________________________ Induction ___________________________________ ___________________________________ ___________________________________ ___________________________________
Electric Current © Copyright NewPath Learning. All Rights Reserved. 94-4407 Visit www.newpathlearning.com for Online Learning Resources. What is Electric Current? The continuous flow of electric charges through a wire or similar material is called electric current. Imagine electric charges moving at a steady rate through a wire. You can count how many charges move past a given point during a certain period of time. If the charges start to flow more quickly, you would count more charges moving past the same point over the same amount of time. Therefore, the rate of flow, or the rate of the current, has increased. Current is Measured in Amps The rate of flow of electrical charges, or current, is expressed in amperes, or amps. The capital letter A is used to symbolize this unit. In equations, amps are symbolized by the capital letter I. 5 0 10 15 20 25 30 35 40 45 50 55 electric current point B point A rate of ow = amount of charges time Quantity Measurement Current I amp A Unit Symbol Unit of Measure Formula Abbreviation 5 0 10 15 20 25 30 35 40 45 50 55 electric current point B point A rate of ow = amount of charges time Quantity Measurement Current I amp A Unit Symbol Unit of Measure Formula Abbreviation DC direct current AC alternating current AC alternating current Two Types of Electrical Current There are two types of electric current, DC and AC. The charges in DC, or direct current, always flow in the same direction. The charges in AC, or alternating current, flow one way and then flow the other way. They are continuously reversing direction. Many batteries use DC electricity. Electric appliances around the house such as microwaves, televisions and washing machines use AC electricity. The electrical power is supplied using alternating current because it is easier to safely control the voltage of this type of current. Electricity in Circuits An electric circuit is a complete path that electricity flows through. For electrical current to continuously flow, the charges must move through a path that is unbroken. This continuous flow of current within a circuit enables us to use electrical power. Our homes and machines use a variety of electric circuits. V 0 10 20 30 electric current point B point A Quantity Measurement Voltage V volt V Unit Symbol Unit of Measure Formula Abbreviation Voltage Voltage is the potential difference between two points in a circuit. Another way to think about it, is the amount of energy released as a charge moves between these two points. Voltage is measured in units called volts. In equations voltage is symbolized by the letter V. zinc electrode carbon electrode electrolyte paste negative terminal positive terminal Dry cell + + + 1.5 volt 12 volt 1.5 volt 12 volt The greater the voltage is, the higher the current. A 1.5-volt battery used in a camera produces less electrical current than a 12-volt battery used in a car.
Pause and Review Fill in the ovals that are labeled with appropriate details. For the ovals that are not labeled, provide both a label and details. © Copyright NewPath Learning. All Rights Reserved. 94-4488 Visit www.newpathlearning.com for Online Learning Resources. Electric Current Power Voltage Electricity DC usage storage type of circuits ____________________________ ___________________ ____________________________ ___________________ ____________________________ ___________________ ____________________________ ___________________ ____________________________ ___________________ ____________________________ ___________________ ____________________________ ___________________ ____________________________ ___________________ ____________________________ ___________________ ____________________________ ___________________ ____________________________ ___________________ Electricity
Electrical Resistance © Copyright NewPath Learning. All Rights Reserved. 94-4490 Visit www.newpathlearning.com for Online Learning Resources. temperature resistance copper wire -40 -40 -30 -20 -10 0 10 20 30 40 50 -20 0 20 40 60 80 100 120 60 70 80 90 100 140 160 180 200 copper wire temperature resistance Electrical Resistance An electrical current is affected by the resistance of the material it is flowing through. Resistance is measured in units called ohms, symbolized by the Greek letter omega (Ω). In equations, r esistance is symbolized with an R. If the voltage remains the same, increasing the resistance will result in a decrease in the current. Factors that affect resistance include an object’s material, temperature, length and thickness. 15 20 30 40 70 OHM S D. C. OHM S 100 20 0 50 0 10 5 4 3 2 1 0 100 80 60 40 20 0 A.C . 300 240 180 120 60 0 Ohm meter Quantity Measurement Resistance R ohm Unit Symbol Unit of Measure Formula Abbreviation Resistance Factors - Material Materials that are good conductors have less resistance, because their electrons are held loosely on the atoms. Materials that are good insulators have a higher resistance because their electrons are held tightly together, and electrical charges have difficulty moving. Resistance = Voltage Current 10 = 120 V 12 A 10 = 30 V 3 A more resistance longer, thinner wire less resistance thicker wire Ohm’s Law Georg Ohm, a Bavarian mathematician and physicist, defined the relationship between resistance, voltage and current. The formula for this relationship, known as Ohm’s Law, is resistance equals voltage divided by current. For example, if the voltage of a toaster is 120 volts and the current is 12 amps, then the resistance of the toaster is 10 ohms. Resistance = Voltage Current 10 = 120 V 12 A 10 = 30 V 3 A Resistance Factors - Temperature Some materials will increase in resistance as the temperature increases. Copper atoms within a wire move faster as they gain thermal energy. This increased molecular movement creates resistance by slowing down the flow of electric charges through the wire. Resistance Factors - Length & Thickness A wire’s length and thickness affect resistance. Longer wires produce more resistance than shorter wires. As the electrical charges move through the length of the wire, they slow down as they collide with the walls of the wire. Thinner wires are more resistant than thicker wires. Thin wires have less area for the charges to flow through, and therefore the current is slower than thick wires.
Pause and Review Use the formula to fill in the missing information below. Show your work. © Copyright NewPath Learning. All Rights Reserved. 94-4490 Visit www.newpathlearning.com for Online Learning Resources. Electrical Resistance Resistance = Voltage Current 10 = 120 V 12 A 10 = 30 V 3 A 220 Volts 11 Ω amps Current : 15 20 30 40 70 OHM S D. C. OHM S 100 20 0 50 0 10 5 4 3 2 1 0 100 80 60 40 20 0 A.C . 300 240 180 120 60 0 Ohm meter Quantity Measurement Resistance R ohm Unit Symbol Unit of Measure Formula Abbreviation 5 amps 20 Ω V Voltage : 180 Volts 9 amps Resistance : Ω
Electrical Power © Copyright NewPath Learning. All Rights Reserved. 94-4491 Visit www.newpathlearning.com for Online Learning Resources. Machines and appliances transform electrical energy into other types of energy. A stove transforms electricity to heat, and a stereo transforms electricity to sound. The rate at which electrical energy is transformed into another type of energy is called electric power. The unit for electrical power is a watt, and the formula is power equals voltage times current. heat sound Electricity: Measurements, Units and Symbols This table is a summary of electric measurements, and their corresponding units, unit symbols and abbreviations in formulas. power (P) = voltage (V) x current (I) 12,000 W = 240 V x 50 A power (P) measured in watts (W) power (P) = voltage (V) x current (I) 12,000 W = 240 V x 50 A power (P) measured in watts (W) Quantity Measurement Voltage E or V volt V Power P wattW Current amp A I R Resistance ohm Unit Symbol Unit of Measure Formula Abbreviation power (P) = voltage (V) x current (I) P = V x I 60 W Quantity Measurement Voltage E or V volt V Power P wattW Current amp A I R Resistance ohm Unit Symbol Unit of Measure Formula Abbreviation power (P) = voltage (V) x current (I) P = V x I 60 W Let’s look at the example of electrical power. If you are referring to the power of a light bulb, then you would use the unit called a watt. You would write 60 watts using a capital W. If you wanted to write out the formula for power, you would use the abbreviation capital P for power. For example, an electric stove top that uses 240 volts and has a current of 50 amps has 12,000 watts of power. A stereo transforms electric power to sound.
Pause and Review Use the formulas to solve the problems. Show your work. Electrical Power © Copyright NewPath Learning. All Rights Reserved. 94-4491 Visit www.newpathlearning.com for Online Learning Resources. 1) A voltage of 120 V is applied to a 60 W light bulb. How much current is in the bulb? 2) A light bulb has .25 A of current using a voltage of 120 V. What is the power rating for this bulb? Power = Voltage x Current 1) A voltage of 120 V is applied to a 60 W light bulb. How much current is in the bulb? 2) A light bulb has .25 A of current using a voltage of 120 V. What is the power rating for this bulb? 1) What is the resistance of an object if a voltage of 20 V produces a current of 5 A? 2) What is the current produced when a voltage of 30 V is applied to an object with a resistance of 6 ohms? Power P wattW Resistance ohm power (P) = voltage (V) x current (I) P = V x I 60 W 1) What is the resistance of an object if a voltage of 20 V produces a current of 5 A? 2) What is the current produced when a voltage of 30 V is applied to an object with a resistance of 6 ohms? Resistance = Voltage Current