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Introductory Video Script Template Lesson Objective Course Semester Unit Lesson SCIENCE 7 A 6 4 Students will explain and demonstrate how electric current produces magnetic forces and how moving magnets produce electric current. CLIP A Visual Audio <Image> Electricity and magnetism are tightly coupled. In fact, you can think of them as two sides of the same coin. http://www.morguefile.com/archive/di splay/57379 <Image> http://www.morguefile.com/archive/di splay/838937 Scientists have observed that a changing electric field creates a magnetic field. <Image Display bulb, then bring in the 2nd image> If you have a circuit and send AC current (alternating current) through with electrons moving back and forth, a changing electric current will be created. A magnetic field will be produced… http://pixabay.com/en/light-bulbcurrent-light-glow-503881/ http://commons.wikimedia.org/wiki/Fi le:DipolMagnet.svg <Image> http://pixabay.com/en/dead-end- Similarly, a change in a magnetic field will create an electric field. blind-alley-stop-arrows-43421/ <Image> Electromagnetic waves travel quite well. For instance the sun provides us with light and heat that travel through space to reach us on the planet Earth. http://pixabay.com/en/bamboodamyang-sunshine-364112/ QUESTION A Both electric and magnetic fields are interdependent, this means: A. they do not rely on one another B. magnetic fields are independent C. neither has an effect on the other D. one field requires the other or one field produces the other Correct answer is D, proceed to CLIP B Incorrect answer (all other), proceed to CLIP E CLIP B Visual Audio <Image> When a charged particle such as an electron is in motion, invisible magnetic lines of force will rotate around it. http://www.morguefile.com/archive/di splay/943980 <Image> Since an electrical current moving through a wire consists of electrons in motion—a magnetic field surrounds the wire. http://pixabay.com/en/ball-abstractpattern-lines-443853/ <Image Zoom in on North, then slowly move downward to South> The direction of a magnetic field has lines of force that move from north to south. http://pixabay.com/en/compass-mapdirection-north-south-32477/ <Image Add to image an arrow pointing left to right, with a (+) on the left and a (-) on the right> Although electrons have a negative charge and move toward the positive terminal on a wire, electric current moves from (+) to (-). http://www.morguefile.com/archive/di splay/934708 QUESTION B The lines of force from a magnetic field run in which direction? A. east to west B. west to east C. north to south D. south to north Correct answer is C, proceed to CLIP C Incorrect answer (all other), proceed to CLIP F CLIP C Visual <Image Zoom in on the center of image, place red circles around the N and S on image> Audio Now let’s look at magnetic force: The magnetic fields of a bar magnet can be revealed by placing iron filings on paper, and a bar magnet underneath. This shows how opposites attract... http://commons.wikimedia.org/wiki/Fi le:Magnet0873.png <Image Place the text “ATTRACT” in This photo shows a closer look at the magnetic the center> field of two bar magnets with unlike poles close together. http://commons.wikimedia.org/wiki/Fi le:Magnetic_field_of_bar_magnets_a ttracting.png <Image Zoom in on center of image, Place the text: “REPEL” in the center> Next, a photo of the magnetic field of two bar magnets with like poles close together. You can see how they repel one another. http://commons.wikimedia.org/wiki/Fi le:Magnetic_field_of_bar_magnets_r epelling.png <Image Zoom in on the open ends, label one “NORTH” and the other “SOUTH”> This horseshoe magnet shows similar force on both sides of the magnet. Although magnetic fields themselves are invisible, these images with iron filings give you a representation of their force. http://commons.wikimedia.org/wiki/Fi le:Magnetic_field_of_horseshoe_ma gnet.png QUESTION C In order for 2 magnets to attract one another, A. their opposite poles must meet B. their same poles must meet C. they can be placed in any direction D. none of the above Correct answer is A, proceed to CLIP D Incorrect answer (all other), proceed to CLIP G CLIP D Visual <Image> Audio Around a wire carrying current, the magnetic field lines form circles. http://pixabay.com/en/hose-couplingpower-cable-strange-206004/ <Image Display images together, then transition text underneath: “COUNTERCLOCKWISE” “CLOCKWISE”> How do you know which direction the magnetic field is going? The direction of the magnetic field coincides with the flow of current in the wire. Counterclockwise or… Clockwise http://pixabay.com/en/cycle-recyclerotation-160072/ <Image Zoom in on the red arrow and the text: Electric current> The following is a way to remember this: The right hand rule is used to predict the direction of a magnetic field. With your thumb pointing upward, this depicts the direction of the current flow. http://commons.wikimedia.org/wiki/Fi le:V-1_right_hand_thumb_rule.gif <Image Zoom in on the fingertips and the blue arrows with the text: Magnetic field> With your hand in the same position, your fingertips are pointing in the direction that the magnetic field will travel. It is a counterclockwise motion. What happens to the direction when you point your thumb down? http://commons.wikimedia.org/wiki/Fi le:V-1_right_hand_thumb_rule.gif QUESTION D __________________________________ determines the direction of the magnetic field. A. The size of the wire B. The amount of volts passing through a wire C. The direction of flow of current through a wire D. The type of insulation on a wire Correct answer is C, SUCCESS alert Incorrect answer (all other), proceed to CLIP H CLIP E Visual <Image> Audio Magnets are surrounded by a magnetic field. http://commons.wikimedia.org/wiki/Fi le:Earth's_magnetic_field_pole.svg <Image Create a circle with an “e” and “-“ inside of it and transition it into and out of the red magnetic field> http://commons.wikimedia.org/wiki/Fi le:Earth's_magnetic_field_pole.svg If an electron were to move through that field, it would experience force and its path would curve. These moving charges now create a magnetic field. <Image> Electric current is a bunch of moving electrons. If you place a wire carrying a current in a magnetic field, there will be force on the wire, and the wire will move. http://commons.wikimedia.org/wiki/Fi le:Simple_electromagnet.gif <Image> Technically speaking, by arranging all of this in the correct fashion, you could make a motor. http://pixabay.com/en/vehiclechrome-technology-193213/ QUESTION E When a wire made of a conducting material passes through a magnetic field, A. the neutrons become active B. an electric current is created in the wire C. nothing will happen D. the magnetic field will disappear Correct answer is B, proceed to CLIP B Incorrect answer (all other), proceed to CLIP F CLIP F Visual Audio <Image> Electric motors use both electricity and magnets to create motion. http://www.morguefile.com/archive/di splay/42014 <Image> The incoming electricity provides power and generates magnetic fields which convert power into motion. http://www.morguefile.com/archive/di splay/600464 <Image> A motor uses electricity to generate motion. The motors in these fans rotate the blades… http://www.morguefile.com/archive/di splay/53465 <Image> A generator uses motion to make electricity. This generator provides electricity to homes. http://www.morguefile.com/archive/di splay/28983 QUESTION F A generator is responsible for the production of which of the following A. Motion B. Magnets C. Motors D. Electricity Correct answer is D, proceed to CLIP C Incorrect answer (all other), INTERVENTION alert, proceed to CLIP B CLIP G Visual <Image> Audio An electromagnet is made by wrapping a wire coil around an iron core. http://commons.wikimedia.org/wiki/Fi le:Solenoid-1.png <Image> A single wire wrapped into a cylindrical wire coil is called a solenoid. The magnetic field inside of it is stronger than the field in a single loop. http://commons.wikimedia.org/wiki/Fi le:Simple_electromagnet2.gif <Image Show images side by side> The strength of the magnetic field can be increased by adding more turns of wire to the solenoid, or by increasing the current. http://commons.wikimedia.org/wiki/Fi le:EnOcean_ECO200_white.jpg http://commons.wikimedia.org/wiki/Fi le:Luftspulen.JPG <Image Display speaker image, then the gauge image> Besides an electric motor, an electromagnet has a variety of applications. Some examples are: Music speakers Gas tank gauges on a dashboard http://pixabay.com/en/speakersaudio-sound-music-playback- 180989/ http://pixabay.com/en/fuel-petrolgas-gauge-empty-full-2741/ QUESTION G The strength of a magnetic field can be increased by which of the following? A. adding more turns to the wire B. decreasing the number of wire turns C. it cannot be increased D. decreasing the current strength Correct answer is A, proceed to CLIP D Incorrect answer (all other), proceed to CLIP F CLIP H Visual Audio <Image> Electric energy is carried by a current, which is a flow of electrons. http://pixabay.com/en/street-lightsjunction-night-neon-600472/ <Image transition in one at a time, powerlines, lights, then phone> The transfer of electrons from one place to another will power your lights, phones, and many other things that you use daily. http://pixabay.com/en/current-energyenvironment-206928/ http://pixabay.com/en/ceiling-lamplamp-chandelier-bulbs-335975/ http://pixabay.com/en/smartphoneiphone-apple-inc-phone-593319/ <Image> This flowing current always produces its own magnetic field. http://pixabay.com/en/magnetismelectromagnetic-field-148997/ <Image Underneath images place text: Magnetism and electric currents are closely “MAGNETIC FIELD” linked in a closed loop, therefore “ELECTRON FLOW”> Electrical currents create magnetic fields… Magnetic fields produce electron flow.... http://pixabay.com/en/magnetic-fieldlines-magnetic-field-454906/ http://pixabay.com/en/abstract-patternlines-wave-106424/ QUESTION H When electrons move, they create a A. proton B. circuit C. chemical reaction D. magnetic field Correct answer is D, SUCCESS alert Incorrect answer (all other), proceed to CLIP G