Magnetism and Sound: Creating Your Own Headphones
Summary
After the unit on Electricity and Magnetism, students are given the opportunity to experience practical applications of the concept as they construct their own headphones and listen to music from their iPods.
CollapseLearning Goals
The student will explore how magnets and coiled wires can create a current.
The student will explore the usefulness of this concept by making their own headphones and witness that current can carry the sound of their iPods.
The student will explore the usefulness of this concept by making their own headphones and witness that current can carry the sound of their iPods.
Context for Use
After the unit on Electricity and Magnetism, students are given the opportunity to experience practical applications of the concept. This is designed for use in a 6th grade classroom. I believe this lab can be accomplished in a 45 minute lab setting. A trip to Radio Shack will be necessary to acquire the amplifier and the cords. I would have students each make their own headphone and plug in to the amplifier with the cords one by one as they complete the work. This way only one set of cords and amplifier are necessary. Students who finish early could attempt the extension or help others.
Description and Teaching Materials
Materials:
Activity 1
-100 cm length of insulated wire
-Bar magnet
-Ampere meter
Activity 2
-About 100 cm length of thin wire
-Paper cup
-2 Neodynium Magnets
-1" bolt
-Wooden dowel
-Audio Amplifier/Speaker (radio shack)
-Cord with 1/8 " two-conductor phone plug at both ends Cord with 1/8" two-conductor phone plug at one end and 2 alligator clips on the other
Magnetism is a form of energy. It can push or pull things. It can even push or pull some of the tiny particles that make up matter: electrons. When you push or pull electrons you get electricity.
Activity 1: A Magnetic Current
1) Begin with a 100-cm length of insulated copper wire. Strip 1 cm of insulation from the ends of the wire.
2)Wrap 20 coils of wire loosely around a bar magnet. Connect the two ends of the wire to an amp meter that will read very low amperage. Next move the magnet back and forth in the loops of wire. Record your observations.
Michael Faraday found out in 1831 that when a magnet moves in a coil of wire, an electric current is produced. Why do we care if magnets moving in a coil of wire create electric current? We can make electricity do something for us while the electrons are moving through a circuit. We can "make" the electrons "heat" a filament in a bulb, causing it to glow and give off light. We can also "make" the current carry sound or produce heat.
Activity 2:
1) Roll about a 4" square of paper around a quarter inch wooden dowel to form a tube. Tape the paper. Next use the sandpaper to remove any coating from both ends of the wire, preparing for a good connection. With the tube still around the dowel, wrap one end with many loops of wire. Leave both ends loose for connecting.
2) Take the cup and punch a hole through the bottom. Push the bolt through this hole, with the head remaining inside the cup. You may use a washer inside if necessary. Next place the two Neodynium Magnets on the protruding end of the bolt and thread the bolt into the tube created in step one. The looped wire should enter into the magnets center hole. Attach the alligator clips on the ends of the coiled wire.
3) Using the cord with phone plugs on both ends, connect the iPod to the input of the amplifier. Connect the second cord to the exterior speaker plug on the amplifier. This cord then connects to your speaker.
Extension: Instead of making the small head phone type of speaker, you could replace the cup with a paper plate. Make a single cut from the outside edge of the plate, into the center. Overlap the slit until you have a cone shape and make a big speaker! Activity directions with pictures (Microsoft Word 495kB Sep16 08)
Activity 1
-100 cm length of insulated wire
-Bar magnet
-Ampere meter
Activity 2
-About 100 cm length of thin wire
-Paper cup
-2 Neodynium Magnets
-1" bolt
-Wooden dowel
-Audio Amplifier/Speaker (radio shack)
-Cord with 1/8 " two-conductor phone plug at both ends Cord with 1/8" two-conductor phone plug at one end and 2 alligator clips on the other
Magnetism is a form of energy. It can push or pull things. It can even push or pull some of the tiny particles that make up matter: electrons. When you push or pull electrons you get electricity.
Activity 1: A Magnetic Current
1) Begin with a 100-cm length of insulated copper wire. Strip 1 cm of insulation from the ends of the wire.
2)Wrap 20 coils of wire loosely around a bar magnet. Connect the two ends of the wire to an amp meter that will read very low amperage. Next move the magnet back and forth in the loops of wire. Record your observations.
Michael Faraday found out in 1831 that when a magnet moves in a coil of wire, an electric current is produced. Why do we care if magnets moving in a coil of wire create electric current? We can make electricity do something for us while the electrons are moving through a circuit. We can "make" the electrons "heat" a filament in a bulb, causing it to glow and give off light. We can also "make" the current carry sound or produce heat.
Activity 2:
1) Roll about a 4" square of paper around a quarter inch wooden dowel to form a tube. Tape the paper. Next use the sandpaper to remove any coating from both ends of the wire, preparing for a good connection. With the tube still around the dowel, wrap one end with many loops of wire. Leave both ends loose for connecting.
2) Take the cup and punch a hole through the bottom. Push the bolt through this hole, with the head remaining inside the cup. You may use a washer inside if necessary. Next place the two Neodynium Magnets on the protruding end of the bolt and thread the bolt into the tube created in step one. The looped wire should enter into the magnets center hole. Attach the alligator clips on the ends of the coiled wire.
3) Using the cord with phone plugs on both ends, connect the iPod to the input of the amplifier. Connect the second cord to the exterior speaker plug on the amplifier. This cord then connects to your speaker.
Extension: Instead of making the small head phone type of speaker, you could replace the cup with a paper plate. Make a single cut from the outside edge of the plate, into the center. Overlap the slit until you have a cone shape and make a big speaker! Activity directions with pictures (Microsoft Word 495kB Sep16 08)
Teaching Notes and Tips
Assessment
This will be used as a performance assessment - students will receive a lab grade for the work completed.
Standards
Standards Match:
6.II.E.1 Electric currents and magnets can exert a force
6.II.E.1 Electric currents and magnets can exert a force