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Virginia García Romero -CEIP El Recreo- Lebrija
MAGNETS
Virginia García Romero -CEIP El Recreo- Lebrija
Are there magnets in nature?
What is magnetic in nature?
Virginia García Romero -CEIP El Recreo- Lebrija
1st Experiment
• Which objects will stick to the magnet?
• Nails
• Scissors
• Plastic caps
• Coins
• Wooden counters
• clips
Virginia García Romero -CEIP El Recreo- Lebrija
• Magnets represent an amazing world which we can´t see.
Virginia García Romero -CEIP El Recreo- Lebrija
• Our senses don´t pick up on magnets but thanks to Science we can understand them.
Virginia García Romero -CEIP El Recreo- Lebrija
• 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.
Virginia García Romero -CEIP El Recreo- Lebrija
• The Earth, the sun and the stars produce a magnetic field which we can detect and study.
Virginia García Romero -CEIP El Recreo- Lebrija
• Computers store data in magnetics CDs.
Virginia García Romero -CEIP El Recreo- Lebrija
• Doctors can see the inside of our bodies thanks to magnetic resonance.
Virginia García Romero -CEIP El Recreo- Lebrija
• 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.
Virginia García Romero -CEIP El Recreo- Lebrija
• Would you like to be surprised by magnets?
Virginia García Romero -CEIP El Recreo- Lebrija
2nd Experiment
• How can we measure
the strength of a
magnet?
Virginia García Romero -CEIP El Recreo- Lebrija
• Let´s learnt about magnets!
• We will follow the historical path.
Virginia García Romero -CEIP El Recreo- Lebrija
• We will discover through history how magnets and electricity joined and scientists changed their ideas and their explanations about magnets.
Virginia García Romero -CEIP El Recreo- Lebrija
• Pliny The Elder (23-79),
the Natural Historian,
described the
magnetite rock and he told
about the Magnes
shepherd´story:
Virginia García Romero -CEIP El Recreo- Lebrija
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.
Virginia García Romero -CEIP El Recreo- Lebrija
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.
Virginia García Romero -CEIP El Recreo- Lebrija
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”.
Virginia García Romero -CEIP El Recreo- Lebrija
3rd Experiment
• To magnetize nails and to observe what´s happen.
Virginia García Romero -CEIP El Recreo- Lebrija
• What are temporary magnets?
Virginia García Romero -CEIP El Recreo- Lebrija
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.
Virginia García Romero -CEIP El Recreo- Lebrija
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.
Virginia García Romero -CEIP El Recreo- Lebrija
4th Experiment
• What are permanent magnets?
Virginia García Romero -CEIP El Recreo- Lebrija
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.
Virginia García Romero -CEIP El Recreo- Lebrija
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.
Virginia García Romero -CEIP El Recreo- Lebrija
We discover a new force.
• Do the two ends of a magnet have the same properties?
Virginia García Romero -CEIP El Recreo- Lebrija
5th EXPERIMENT
• What are the two ends of a magnet like?
Virginia García Romero -CEIP El Recreo- Lebrija
POLES
• 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".
Virginia García Romero -CEIP El Recreo- Lebrija
THE RULES
• Same colour poles repel.
• Different colour poles attract.
Virginia García Romero -CEIP El Recreo- Lebrija
6th Experiment
• Are human beings sensitive to magnets?
Virginia García Romero -CEIP El Recreo- Lebrija
• We are not sensitive to magnets so, we need instruments to detect them and study their characteristics.
Virginia García Romero -CEIP El Recreo- Lebrija
A big leap in history (XIX c.)
• Faraday introduced a new concept:
MAGNETIC FIELD
Virginia García Romero -CEIP El Recreo- Lebrija
About Faraday
• Date :1791-1867
• His biggest achievement was the concept of magnetic and electric fields.
Virginia García Romero -CEIP El Recreo- Lebrija
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?
Virginia García Romero -CEIP El Recreo- Lebrija
• 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.
Virginia García Romero -CEIP El Recreo- Lebrija
• The compass is the instrument which helps us to detect the magnetic field.
Virginia García Romero -CEIP El Recreo- Lebrija
7th Experiment• Can we make a compass?
Virginia García Romero -CEIP El Recreo- Lebrija
Virginia García Romero -CEIP El Recreo- Lebrija
The Earth is a great magnet. Its magnetic field is like a bar magnet at its center.
Virginia García Romero -CEIP El Recreo- Lebrija
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.”
Virginia García Romero -CEIP El Recreo- Lebrija
Virginia García Romero -CEIP El Recreo- Lebrija
• What is near the Geographic North Pole, a Magnetic North or a Magnetic South?
Virginia García Romero -CEIP El Recreo- Lebrija
• 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).
Virginia García Romero -CEIP El Recreo- Lebrija
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).
Virginia García Romero -CEIP El Recreo- Lebrija
8th Experiment
• How does a toy lift work?
Virginia García Romero -CEIP El Recreo- Lebrija
9th Experiment
• Can we make an engine work with magnets?
Virginia García Romero -CEIP El Recreo- Lebrija
QUIZ TIME
• 1. Which objects will not stick to the magnet?
Virginia García Romero -CEIP El Recreo- Lebrija
• 2. Magnets should never be held in front of which object?
a) Telephoneb) Computersc) Booksd) Light
Virginia García Romero -CEIP El Recreo- Lebrija
3. Which picture shows how objects stick to bar magnets?
Virginia García Romero -CEIP El Recreo- Lebrija
• 4. What colour would a South Pole be on a magnet?
a) Redb) Greenc) Greyd) Blue
Virginia García Romero -CEIP El Recreo- Lebrija
• 5. What is another word for "not sticking"?
a) Avoidingb) Attractingc) Repellingd) Running away
Virginia García Romero -CEIP El Recreo- Lebrija
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
Virginia García Romero -CEIP El Recreo- Lebrija
• 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
Virginia García Romero -CEIP El Recreo- Lebrija
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