Magnetic Fields

Magnetic Fields

Learners can:

• construct a model of a magnetic field

• interpret field lines in magnetic field models

Grab These Materials!

Can anyone figure out how to make a pendulum with the materials listed on the previous slide?

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What is a pendulum?

Build a magnetic pendulum.

1. Fit the bottom of the pendulum arm into the slot in the base.

2. Use the small ring to hang the pendulum string from the arm.

3. Place one bar magnet on either side of the large ring with opposite poles facing each other.

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Build a Magnetic Pendulum

​What are some things you notice about the pendulum you created?


-How does the pendulum orient itself?

-Move the pendulum to a few different places in your house. Does it orient in the same way?

-Put it next to your refrigerator, does that change anything?

Magnetic Fields

All magnets produce a magnetic field. A magnetic field is the area surrounding an object where you can detect magnetic force. Scientists create models of magnetic fields by drawing field lines. Field lines show the direction of magnetic force around an object, with the lines always pointing from the magnet's north pole toward its south pole.

​Does Earth Generate Any Magnetic Fields?

Earth is essentially a giant magnet because of the iron in the core. Earth's magnetic field is massive. The points of focus of Earth's magnetic field are the magnetic north pole and the magnetic south pole. Earth's magnetic field does not align perfectly with the geographic North and South Poles. The magnetic axis differs from Earth's axis of rotation by about 11 degrees.

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Earth

​Magnetism Video!

https://ccalms.blob.core.windows.net/production/31448/e95a3847-68b7-4849-9fc5-39d1d588cf37-20240105145216004-Earth_s_Magnetic_Field_(SD_Large_-_WEB_MBL_(H264_1500)).mp4

Draw

Draw what you think Earth would look like if it didn't have a magnetic field surrounding it!

​Time to experiment with the iron filings. Let's check out this video first!

https://ccalms.blob.core.windows.net/production/31448/9a292bdd-ed16-4eee-83d6-fcb5c18c7659-20240111121820731-Science7_U1_fields_filings.mp4

​Note that the filings create patterns in three dimensions. Magnetic fields exist in three dimensions, so the iron filings follow those forces. The pattern created by the iron filings resembles the field lines you would draw to model the magnetic field.

Multiple Choice

The lines in a magnetic field flow from the north pole to the south pole.

The diagram below represents a magnet and its magnetic field. Where is the south pole of the magnet?

• A

• B

• C

​Does anyone know what this is called?

Does anyone know how this happens?

Check out this video!

https://ccalms.blob.core.windows.net/production/31448/7361ca30-c649-403b-b0a7-dbec4036c3dc-20240112113822709-Magnetism__Auroras_(SD_Large_-_WEB_MBL_(H264_1500)).mp4