Lesson 2 Page 1
Completion requirements
Discover: The Mysteries of Magnetism
Evidence of Magnetic Fields
Magnetic fields are invisible. How can we know a magnetic field is really there? We can "see" the evidence of a magnetic field indirectly. Lodestone and iron filings, a compass, or magnetic sensor show you that a magnetic field is there. Another evidence of a magnetic field is the northern lights.
Ancient people first discovered the mysterious force of magnetism in the natural mineral magnetite. Magnes was herding sheep when his metal staff stuck to a black rock. To find out what was happening, he studied the rock. He found that chunks of magnetite (also known as lodestone) will attract each other and iron.
Explorers use compasses to help know where they are going. A compass needle is attracted to Earth's North pole so it will line up with the magnetic field lines of the Earth.
Around 4,000 years ago, the Chinese learned how to make the first compass. They made a needle out of magnetite (or magnetized a metal by stroking it against magnetite in one direction.) They floated it in water. The needle would always point in the North/South direction.
Around 4,000 years ago, the Chinese learned how to make the first compass. They made a needle out of magnetite (or magnetized a metal by stroking it against magnetite in one direction.) They floated it in water. The needle would always point in the North/South direction.
Video
Watch this ADLC Digital Lesson on Measuring Magnetism. Magnetism is a force that is difficult to understand because you cannot see it. However, if you have the right tools, you can measure magnetism.
ADLC - Elementary Science Measuring Magnetism
Did you know that the Earth is a giant magnet?
When fast-moving electric particles from the Sun move through the magnetic field of the Earth, the night sky in the northern hemisphere can glow green, blue, or red. Many people call this beautiful glowing night sky the "northern lights". Of course, if you were in Antarctica, you would see the “southern lights”!
How can magnetism be seen and experienced?
Materials
- Magnetic Kit Items: 2 small bar magnets, bent staples, compass
- Website: Magnetic Field Lines
Check Your Answers
Once you have completed this activity, check your answers below.
Magnetic field images attributed to Geek3 Wikimedia
Magnetism Evidence Table |
| Item Tested | What Happened? | Why Did it Happen? |
| 1. Opposite Pole Magnets | They attract each other and pull each other together. | Invisible magnetic fields surround magnets. Unlike or opposite magnetic poles will pull each other together. |
| 2. Like Pole Magnets | The magnets repel or push each other apart. | Invisible magnetic fields surround magnets. Like magnetic poles will push each other apart. |
| 3. Opposite Magnetic Poles - Bent Staples 1 | Staples arrange themselves according to the magnetic field of the magnet. |
There are invisible magnetic field lines around a magnet.   |
| 4. Like Magnetic Poles - Bent Staples 2 | Staples arrange themselves according to the magnetic field of the magnet. |
There are invisible magnetic field lines around a magnet.  |
| 5. Different Shape Magnets | Staples arrange themselves according to the magnetic field of the magnet. | There are invisible magnetic field lines around a magnet. The magnetic fields are the same shape as above depending on the poles of the magnet. |
| 6. Compass Needle |
The compass needle points to the pole of the bar magnet.
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Like magnetic poles are attracted to each other.
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