Script for
Magnetism

This slideshow is designed for K-3rd grades. Review what is physics.  Discuss with the students the subject of magnets.  What is a magnet?  Where does the force come from? Go over attract and repel. 

Slide 1. 

·       The Earth has Magnetic Poles.  There is geologic evidence of this in rocks that are extruded from divergent plate boundaries in the ocean.

·       Compasses use the Earth’s magnetic poles to help find direction. Explain that a magnet has a north pole and a south pole. North and south will attract, but "like" poles will repel each other. Magnetism is created when electrons "spin" in the same direction.

·       In some substances this occurs naturally (iron, nickel, and cobalt), but in most substances it does not. Items can be magnetized by hitting them so that all the electrons "spin" in the same direction.

·       The Earth acts as a huge magnet. As a result, pieces of iron or steel which lie in a North - South direction often became magnetized by "induction." Induction means the "forcing" of an object. If such objects are jolted while in this position, their molecules line up and they become more easily magnetized. Thus, some materials can be magnetized by tapping them with a hammer.

Slide 2.  Early History of Electricity and Magnetism

·       Go over history with the emphasis on how difficult to determine difference between Electricity and magnetism

·       A Medieval seaman's code declares that any sailor caught tampering with the ships lodestone ".....shall, if his life be spared, be punished by having the hand which he most uses, be cut and fastened by a dagger or knife thrust through it, to the mast or principal timber of the ship....." In the history of science, this strict code is vivid evidence of human's early dependence upon magnetism. Lodestone was used for navigational purposes in a compass and without a compass, captains could not find north.

Slide 3. 

·       The use of magnetism can be traced to Emperor Hoang-Ti around 2635 BC.  According to the legend, he lost his way in a thick fog chasing the rebellious Prince Tchiyeou. 

·       In order to navigate in the fog, he used a floating piece of loadstone, which is naturally magnetic.  The compass was put on his chariot, enabling him to locate and later kill the Prince.

Slide 4.

·       Thales of Miletus  (according to Aristotle’s writings in 300’s BC) discovered the attractive properties of amber when the amber was rubbed with cloth.  This was the beginning of investigating a “charged” object.  He was experiencing what we now call “static electricity.”

·       The ancient Greeks noted magnetism in the mineral magnetite or lodestone. In a Greek myth, a shepherd boy named Magnes, thrust his iron staff into a hole containing magnetite and found to his dismay that he was unable to remove it. (Students can find magnetite if they take a magnet to some beaches and drop it in the sand. What sticks to the magnet is usually magnetite.) Socrates and Plato noted magnetism in some of their writings. It is also said that 2,300 years ago, Ptolemy Philadelphos had a temple at Alexandria made from magnetite so he could suspend a statue in mid-air. His experiment didn't work. Magnetite loses its magnetic quality over time.

Slide 5.  

·       A long time passed before humans learned how to harness the energy of electricity and magnetism.  They saw that lightning was attracted to certain areas and would just come out of the sky.  But they did not know what caused it.

Slide 6.   

·       In 1492 Christopher Columbus discovered that the declination of the compass needle varied for different parts of the world.  The compass was an important navigational tool.

·       Columbus like most navigators needed a compass so they did not go off course.  However, since Columbus was looking for India, the compass was not much help.

Slide 7.  

·       Gilbert wrote the first book on magnets and described the Earth as a big magnet with forces being generated. 

Slide 8.

·       Magnetism has to be felt to understand the force that is created. 

·       Emphasize that you have to feel magnetic forces; how does it act with other magnets; is some magnets strong than others, and what causes magnetism.

Slide 9. 

·       Make sure students know that attract is between North and South.

·       Repel is between north and north or south and south.     

Slide 10.

·       This slide show the pattern created by north and south on a bar magnet.

Slide 11. 

·       Diagram of an atom.  The figures on the outside are the electrons.  Go over charges for each particle. 

·       The spinning of electrons causes magnetism. 

·       You can’t see the energy flowing from the electrons on a magnet, unlike the “electrons” you can see when you do experiments with electricity (static).  This is a diagram representing the flow of electrons or energy from a bar magnet.  Discuss attract and repel.  Attract-coming together, repel-pushing apart. 

Slide 12.

·       Examples of different types of magnets.  Notice horse shoe magnet is like a curved bar magnet. Force comes only at the ends.

Slide 13.

·       Ring magnets have the north and south on either side of the long side.  So when north and north (or south or south) side are next to each other, it will repel.  It levitates or floats!

Slide 14. 

·       This slide shows that  most substances have electrons that spin half in one direction and half the other direction.  This allows the spin to “cancel”  the force making in neutral. 

·       In 3 substances, nickel, cobalt and iron they spin in the same direction giving it a magnetic force.

 Slide 15. 

·       cow-shaped like a capsule.  Discuss further why this is called a cow magnet. 

·       Cows have 4 stomachs and ranchers use the cow magnet to extract metal from ingested hay (bales) so that there is little damage to the stomachs.        

Slide 16.  

·       Review slide after students do activity to make sure they know which items are magnetic.

·       Might want to ask students what is magnetic around the room.

Slide 17.    Hairy Monster

·       This is a picture of magnetite (a mineral) surrounding a magnet.  The pattern is caused by the force field.

·       You can read the storybook, “Hairy Monster” to review major principles.  

Slide 18.    History of Electromagnetism

     ·       This section is for older grades where it discusses the connection of Electricity and Magnetism.  This breakthrough in technology changed human’s ability to control its world through electromagnetism. We are still learning more about how electromagnetism is part of the human experience. 

Slide 19

·       End with electromagnetism.  Electricity plus magnetism equals electromagnetism.  You can review the electromagnetic wave spectrum.  All of these "waves" are generated by the electromagnetism force of nature.