Magnetic Field Viewer

Physics:	Magnetic Field lines
Grade Range:	Elementary School, Middle School, High School
Format:	Hands-on

This demonstration topic is broad enough to be hands-on at all grade and age levels. Encourage students to think about how the lines are generated, why magnets can make field lines, and what is happening with this demonstration.

Materials

• Magnetic Field Viewer
• Small Magnets

Safety Precautions

Please read the General Safety Precautions section of the Demonstration Safety page before performing this demonstration.

This demonstration has small parts, so practice caution with children under the age of four.

Demonstration

1. Set out the Magnetic Field Viewer and two magnets. Let students come up and slide one of the magnets inside the magnetic field viewer. What do they see happen to the suspended iron filings?
2. Ask students some questions before providing an explanation. Possible questions are:
   • What causes the iron filings to line up?
   • Why don't the iron filings clump together where the magnet is at?
   • Why does the effect go away when the magnet is removed?
   • What do they think it would look like if you put two magnets in that are attracted to each other, or have opposite poles aimed towards each other? Test it, and compare the findings to the hypothesis.
   • What do they think it would look like if you put two magnets in that are repelled by each other, or have like poles aimed towards each other? Test it, and compare the findings to the hypothesis.

Why This Works

All permanent magnets have a Magnetic Field, which is a "force field" made by the magnetic force it generates. Magnets have positive and negative ends, and their magnetic fields travel from the positive end to the negative end. The magnetic field applies a force on other electromagnetic things, which is why two magnets put near each other will repel (same-side) or attract (opposite-side) each other. The direction of the magnetic field can be found by tracing the Magnetic Field Lines, which are a way to visualize the magnetic field around a magnet.

When a magnet is placed inside the magnetic field viewer, the iron filings all line up with the magnetic field and create the magnetic field lines. This shows us what the magnetic field of the magnet looks like, and gives us a clear visual when learning about magnetism!

Additional Information

• For older students, ask them to think about this demonstration in regards to what they have learned about electromagnetism. This demonstration can help them visually make the connections between the learned topics and their applications.
• This demonstration pairs well with the Mystical Rods, the Accelerators and the Copper Tube and Magnet demonstrations.