magnets

Virginia García Romero -CEIP El Recreo- Lebrija

MAGNETS

Are there magnets in nature?

What is magnetic in nature?

1st Experiment

• Which objects will stick to the magnet?

• Nails

• Scissors

• Plastic caps

• Coins

• Wooden counters

• clips

• Magnets represent an amazing world which we can´t see.

• Our senses don´t pick up on magnets but thanks to Science we can understand them.

• Do you know that magnets are one of the most important forces which move our world?

• There is a magnet or and electromagnet inside an electric engine.

• The Earth, the sun and the stars produce a magnetic field which we can detect and study.

• Computers store data in magnetics CDs.

• Doctors can see the inside of our bodies thanks to magnetic resonance.

• Einstein said in his autobiography that when he was five years old he was very surprised when his father gave him a compass as a present.

• Would you like to be surprised by magnets?

2nd Experiment

• How can we measure

the strength of a

magnet?

• Let´s learnt about magnets!

• We will follow the historical path.

• We will discover through history how magnets and electricity joined and scientists changed their ideas and their explanations about magnets.

• Pliny The Elder (23-79),

the Natural Historian,

described the

magnetite rock and he told

about the Magnes

shepherd´story:

There is a story that a shepherd from the island of Grete was the first to discover lodestone when

his crook, which

had an iron tip,

was pulled towards

a stone when he

passed over it.

The shepherd ´s name was Magnes.

Platon (fouth century before Christ)

The stone not only attracts iron rings, the stone transmits its power to attract other rings. Sometimes we can see many iron objects joined with others like a chain, and all of them receive the power of the stone.

We can observe

• Nails are magnetized when they touch the magnets.

• Some objects stick to magnets.

• Objects will pull towards the magnets.Another name for

sticking is "attract”.

3rd Experiment

• To magnetize nails and to observe what´s happen.

• What are temporary magnets?

Temporary Magnets

• Temporary magnets are those which act like a permanent magnet when they are within a strong magnetic field, but lose their magnetism when the magnetic field disappears. Examples

would be paperclips

and nails and other soft

iron items.

The first model of a magnetic force• Tito Lucrecio Caro (99-55 B.C.) (Julio

César´s contemporary) describes in his poem “The Rerum Natura”(The nature of the things) that he has seen pieces of iron move inside a bronze vessel when this vessel was approched by a magnetic stone.

4th Experiment

• What are permanent magnets?

Permanent Magnets

• Permanent magnets are those we are most familiar with, such as the magnets hanging onto our refrigerator doors. They are permanent in the

sense that once they

are magnetized, they

retain a level of

magnetism.

Tito Lucrecio Caro…

• He describes some pieces of iron which have been in contact with a magnetic stone, they are repeled when they are approched by the stone.

We discover a new force.

• Do the two ends of a magnet have the same properties?

5th EXPERIMENT

• What are the two ends of a magnet like?

• All magnets have ends or sides.

• Another name for these ends or sides is "poles".

• The two ends of the magnet are different.

The red ends are called the "north pole".

The blue ends are called the "south pole".

THE RULES

• Same colour poles repel.

• Different colour poles attract.

6th Experiment

• Are human beings sensitive to magnets?

• We are not sensitive to magnets so, we need instruments to detect them and study their characteristics.

A big leap in history (XIX c.)

• Faraday introduced a new concept:

MAGNETIC FIELD

About Faraday

• Date :1791-1867

• His biggest achievement was the concept of magnetic and electric fields.

The magnet rules

• Alike poles repel each other.

• Different poles attract each other.

• This happens without touching them.

• Why does a magnet know that

there is a magnet close?

• Human beings have always been interested about how magnets work.

• And human beings always thought that there was something that we couldn´t see but did exist. This something was the magnetic field.

• The compass is the instrument which helps us to detect the magnetic field.

7th Experiment• Can we make a compass?

The Earth is a great magnet. Its magnetic field is like a bar magnet at its center.

The Earth is a magnet because it contains a lot of iron.

• The moon does not have as much iron, so it is not a magnet. Your compass would not work on the moon.”

• What is near the Geographic North Pole, a Magnetic North or a Magnetic South?

• Think of the Earth's North Pole (which is geographically located in the artic) as the "south end of a bar magnet".This is why the North tip of a compass needle is attracted to the vicinity of the "North Pole".

• As we know, with

magnets, "opposite

ends attract“

(N is attracted to S).

The red pole of a magnet points to the geographic North pole.

A compass needle is a magnet too - so it's S end will be attracted to the "North" side of your unmarked magnet (and vice versa).

8th Experiment

• How does a toy lift work?

9th Experiment

• Can we make an engine work with magnets?

QUIZ TIME

• 1. Which objects will not stick to the magnet?

• 2. Magnets should never be held in front of which object?

a) Telephoneb) Computersc) Booksd) Light

3. Which picture shows how objects stick to bar magnets?

• 4. What colour would a South Pole be on a magnet?

a) Redb) Greenc) Greyd) Blue

• 5. What is another word for "not sticking"?

a) Avoidingb) Attractingc) Repellingd) Running away

Interesting links

• http://ed101.bu.edu/StudentDoc/current/ED101fa10/sjay0601/content1.html

• http://blps.groupfusion.net/modules/groups/homepagefiles/cms/14571/File/Magnets%20Webquest/Magnets_Webquest.html

• http://www.kidskonnect.com/subject-index/15-science/90-magnets.html

• http://www.buzzle.com/articles/facts-about-magnets.html

• http://www.csicenlaescuela.csic.es/proyectos/magnetismo.htm

• http://www.bbc.co.uk/schools/scienceclips/ages/7_8/magnets_springs.shtml

• http://www.bbc.co.uk/schools/teachers/ks2_lessonplans/science/magnets_springs.shtml

Bibliography

• Book: What Makes A MagnetAuthor: Franklyn M. BranleyIllustrator: True KelleyPublisher: HarperCollinsPublication Date: July 1996Pages: 32 PagesGrade Range: Kindergarten, First Grade and Second GradeISBN: 978-0060264413

magnets

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