Unit 7 Forces and Motion Lesson 5 Electromagnetism Unit 7 Forces and Motion Lesson 5

Electromagnetic Relationships Create a Magnet Word Graphic Organizer in your notebook for the word electromagnetism. Which two words do you think of when they see that word?

Electromagnetic Relationships Create a Magnet Word Graphic Organizer in your notebook for the word electromagnetism. Which two words do you think of when they see that word? Electricity and Magnetism

Electromagnetic Relationships Create a Magnet Word Graphic Organizer in your notebook for the word electromagnetism. Which two words do you think of when they see that word? Electricity and Magnetism Label the left side of the magnet with electro- and the right side with –magnetism. On the electro- side, draw pictures and write words associated with electricity. On the –magnetism side, write words and draw pictures related to magnets. When finished, share your magnets with your table.

Conversion Misconception Some students confuse the terms motor and generator. To help with this, try to remember this: Electrical Energy to Mechanical Energy = Motor (E-E-M-E-M which resembles the sound a motor makes!) Mechanical Energy to Electrical Energy = Generator (M-E-E-E- Generator).

Conversion Misconception Some students confuse the terms motor and generator. To help with this, try to remember this: Electrical Energy to Mechanical Energy = Motor (E-E-M-E-M which resembles the sound a motor makes!) Mechanical Energy to Electrical Energy = Generator (M-E-E-E- Generator). Make a poster of each with your table to help remember the difference.

Generating Diagrams Generators use magnets to produce electricity. These are some of the different types of power generators: wind turbines, hydroelectric plants, and nuclear and fossil fuel burning plants.

Generating Diagrams Generators use magnets to produce electricity. These are some of the different types of power generators: wind turbines, hydroelectric plants, and nuclear and fossil fuel burning plants. All of these methods of generating electricity rely on converting movement to electricity. With your table, choose a type of power generator and draw a picture of how the movement in the method produces electricity.

Introduction Welcome to the lesson, "Electromagnetism." In this lesson, you'll learn about the relationship between electricity and magnetism. EQ: What is electromagnetism? The vocabulary words for this lesson are electromagnetism, solenoid, electromagnet, electric motor, electromagnetic induction, electric generator, and transformer.

Vocabulary Electromagnetism: The interaction between electricity and magnetism Solenoid: A coil of wire with an electric current in it Electromagnet: A coil that has a soft iron core and that acts as a magnet when an electric current is in the coil Electric Motor: A device that converts electrical energy into mechanical energy Electromagnetic Induction: The process of creating a current in a circuit by changing the magnetic field Transformer: A device that increases or decreases the voltage of an alternating current Electric Generator: A device that converts mechanical energy into electrical energy

Cause and Effect After you’ve read through the section on electromagnetism, predict how someone might make a magnet that can be switched on and off. Think of how you can apply the cause-and-effect relationship of electromagnetism after re-reading page 456-457.

Cause and Effect After you’ve read through the section on electromagnetism, predict how someone might make a magnet that can be switched on and off. Think of how you can apply the cause-and-effect relationship of electromagnetism after re-reading page 456-457. Because electromagnets rely on electricity to make them magnetic, the presence of an electric current controls whether the magnet is on or off. Disconnecting the electricity would turn the electromagnet off.

Cause and Effect After you’ve read through the section on electromagnetism, predict how someone might make a magnet that can be switched on and off. Think of how you can apply the cause-and-effect relationship of electromagnetism after re-reading page 456-457. Because electromagnets rely on electricity to make them magnetic, the presence of an electric current controls whether the magnet is on or off. Disconnecting the electricity would turn the electromagnet off. What did Oersted discover in 1820?

Cause and Effect After you’ve read through the section on electromagnetism, predict how someone might make a magnet that can be switched on and off. Think of how you can apply the cause-and-effect relationship of electromagnetism after re-reading page 456-457. Because electromagnets rely on electricity to make them magnetic, the presence of an electric current controls whether the magnet is on or off. Disconnecting the electricity would turn the electromagnet off. What did Oersted discover in 1820? Oersted discovered that electric current produces a magnetic field and that the direction of the magnetic field is dependent on the direction of the current.

Cause and Effect What did Oersted discover in 1820? Oersted discovered that electric current produces a magnetic field and that the direction of the magnetic field is dependent on the direction of the current. How does an electromagnet work?

Cause and Effect What did Oersted discover in 1820? Oersted discovered that electric current produces a magnetic field and that the direction of the magnetic field is dependent on the direction of the current. How does an electromagnet work? An iron core has current-carrying wire wrapped around it. The current causes the iron core to become magnetic. The entire coil-wrapped mechanism becomes an electromagnet.

Visualizing Electromagnets After you’ve read how electromagnets are used, visualize the examples. Explain what you think each device does and how electromagnets are used in them. You may draw a picture showing how they think each example works and how each uses electromagnets.

Visualizing Electromagnets After you’ve read how electromagnets are used, visualize the examples. Explain what you think each device does and how electromagnets are used in them. You may draw a picture showing how they think each example works and how each uses electromagnets. How does visualizing help you understand what you’re learning about?

Visualizing Electromagnets After you’ve read how electromagnets are used, visualize the examples. Explain what you think each device does and how electromagnets are used in them. You may draw a picture showing how they think each example works and how each uses electromagnets. How does visualizing help you understand what you’re learning about? It helps you stop and thin and figure things out.

Why It Matters The tube of an MRI machine contains electromagnets much like the simple solenoids you’ve learned about. How are an MRI and a simple solenoid similar?

Why It Matters The tube of an MRI machine contains electromagnets much like the simple solenoids you’ve learned about. How are an MRI and a simple solenoid similar? They both form a tubular shape. They both rely on electric current.

Why It Matters The tube of an MRI machine contains electromagnets much like the simple solenoids you’ve learned about. How are an MRI and a simple solenoid similar? They both form a tubular shape. They both rely on electric current. The hydrogen atoms in the human body acts like compasses in the presence of a strong magnetic field. When the magnetic field is removed, the hydrogen atoms return to their original positions and emit a radio signal while doing so. These radio waves are what an MRI detects and what allows the machine to see inside us.

AC versus DC How many of you have seen the acronyms AC and DC before in scientific context?

AC versus DC How many of you have seen the acronyms AC and DC before in scientific context? DC stands for Direct Current and AC stands for Alternating Current. Direct current is an electric charge that flows in one direction only. Direct current is produced by batteries and by DC generators, such as a cell phone charger.

AC versus DC How many of you have seen the acronyms AC and DC before in scientific context? DC stands for Direct Current and AC stands for Alternating Current. Direct current is an electric charge that flows in one direction only. Direct current is produced by batteries and by DC generators, such as a cell phone charger. Alternating current is a flow of electric charges that reverses direction at regular intervals. The current that enters homes and schools is an alternating current.

Motors Study the diagram of the motor after re-reading page 461. Use the diagram to describe how electric energy from the battery is used to make the armature move.

Motors Study the diagram of the motor after re-reading page 461. Use the diagram to describe how electric energy from the battery is used to make the armature move. Electric current from the battery moves through the wires and then to the armature. This causes the armature to become an electromagnet. Since magnets surround the armature, its poles are repelled by the like poles in the magnet. The commutator keeps changing the poles of the electromagnet so that it continually moves.

Induction Turn to page 462. Why is induction considered to be the opposite of the process that produces an electromagnet?

Induction Turn to page 462. Why is induction considered to be the opposite of the process that produces an electromagnet? To make an electromagnet, you use electric current to produce a magnetic field. The process of induction uses a changing magnetic field to produce an electric current.

Induction Turn to page 462. Why is induction considered to be the opposite of the process that produces an electromagnet? To make an electromagnet, you use electric current to produce a magnetic field. The process of induction uses a changing magnetic field to produce an electric current. What is the difference between a step-up transformer and a step- down transformer?

Induction Turn to page 462. Why is induction considered to be the opposite of the process that produces an electromagnet? To make an electromagnet, you use electric current to produce a magnetic field. The process of induction uses a changing magnetic field to produce an electric current. What is the difference between a step-up transformer and a step- down transformer? The difference is the number of coils on the primary and secondary sides. A step-up transformer has more coils on the secondary side and therefore has a greater voltage output than input.

Induction What is the difference between a step-up transformer and a step- down transformer? The difference is the number of coils on the primary and secondary sides. A step-up transformer has more coils on the secondary side and therefore has a greater voltage output than input. Discuss how you knew the transformers in the Do the Math example on page 463 are step-down transformers and not step-up transformers.

Induction What is the difference between a step-up transformer and a step- down transformer? The difference is the number of coils on the primary and secondary sides. A step-up transformer has more coils on the secondary side and therefore has a greater voltage output than input. Discuss how you knew the transformers in the Do the Math example on page 463 are step-down transformers and not step-up transformers. In both examples, the wire wraps around the primary coil more times than the secondary coil. In the sample, the voltage on the primary coil is 300 volts and the voltage on the secondary coil is less- 180 volts.

Induction Discuss how you knew the transformers in the Do the Math example on page 463 are step-down transformers and not step-up transformers. In both examples, the wire wraps around the primary coil more times than the secondary coil. In the sample, the voltage on the primary coil is 300 volts and the voltage on the secondary coil is less- 180 volts. How can you use this information to help evaluate the accuracy of the answer you got in your You Try It calculation?

Induction Discuss how you knew the transformers in the Do the Math example on page 463 are step-down transformers and not step-up transformers. In both examples, the wire wraps around the primary coil more times than the secondary coil. In the sample, the voltage on the primary coil is 300 volts and the voltage on the secondary coil is less- 180 volts. How can you use this information to help evaluate the accuracy of the answer you got in your You Try It calculation? The voltage on the secondary coil should be less than the voltage on the primary coil (500 volts).

Misconceptions on Motors and Generators Some of you may think that both motors and generators produce electricity because they are made of the same parts. A generator changes mechanical energy into electrical energy (as happens at a power plant), and a motor changes electrical energy into mechanical energy (as in a fan). How could you explain the difference in motors and generators in your own words?

Misconceptions on Motors and Generators Some of you may think that both motors and generators produce electricity because they are made of the same parts. A generator changes mechanical energy into electrical energy (as happens at a power plant), and a motor changes electrical energy into mechanical energy (as in a fan). How could you explain the difference in motors and generators in your own words? A generator uses movement to produce electrical energy while a motor uses electrical energy to produce movement.

Energy in Electricity What role does kinetic energy play in the production of electricity?

Energy in Electricity What role does kinetic energy play in the production of electricity? Kinetic energy turns the turbine in a generator.

Energy in Electricity What role does kinetic energy play in the production of electricity? Kinetic energy turns the turbine in a generator. What other sources of mechanical energy might you be able to use to produce electricity?

Energy in Electricity What role does kinetic energy play in the production of electricity? Kinetic energy turns the turbine in a generator. What other sources of mechanical energy might you be able to use to produce electricity? A treadmill, a bicycle, a hamster wheel, a hand crank, etc.

Energy in Electricity What role does kinetic energy play in the production of electricity? Kinetic energy turns the turbine in a generator. What other sources of mechanical energy might you be able to use to produce electricity? A treadmill, a bicycle, a hamster wheel, a hand crank, etc. What would be some of the pros and cons of using these sources of mechanical energy?

Energy in Electricity What role does kinetic energy play in the production of electricity? Kinetic energy turns the turbine in a generator. What other sources of mechanical energy might you be able to use to produce electricity? A treadmill, a bicycle, a hamster wheel, a hand crank, etc. What would be some of the pros and cons of using these sources of mechanical energy? Pros: It would be easy and inexpensive to use. Cons: Some of them require physical activity, so the person (or hamster) would get tired after doing it for a long time. It probably would not produce very much electricity.

Summary Electromagnetism is the interaction between electricity and magnetism. When an electric current is in a coiled wire called a solenoid, the solenoid has a magnetic field. An electromagnet is a solenoid that has an iron core. When current is in the wire, the core becomes magnetized, giving an electromagnet a much stronger magnetic field than a solenoid alone. Changing the magnetic field around a wire can produce an electric current. This process is known as electromagnetic induction.

Summary Electromagnets are used in electric motors, which convert electrical energy into mechanical energy. Electric motors can be found in power tools, kitchen appliances, and many other devices. Electric generators convert mechanical energy into electrical energy. They vary in size from the tiny generator in a hand-cranked flashlight to the giant generators in hydroelectric dams and power plants. Transformers use electromagnets to increase or decrease the voltage of an electric current. The electromagnets in transformers have iron rings that are usually circular or square, with two wire coils. Step-up transformers increase voltage, while step-down transformers decrease voltage.

Tonight’s Homework Create a mind map to connect key ideas from the lesson. Write the term electromagnetism in the center of the map. Then write details that relate to electromagnetism in the branches of the map.