
Bar Magnets, Compasses, and Bermuda Triangles
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What happens when a bar magnet's field collides with the Earth's magnetic field? In some spots the two fields add together. In others they cancel completely. Those dead zones have no magnetic pull at all.
You place a bar magnet on a large sheet of paper. Then you trace the direction a small compass needle points at dozens of locations. Connecting those points reveals curved field lines stretching across the page.
Some lines bend toward the magnet. Others follow the Earth's field. Where the two fields are equal and opposite, the compass spins freely. These null points are the "Bermuda Triangles" of your map.
Hypothesis
The hypothesis is that the magnetic field of a bar magnet will interact with the Earth's magnetic field to form a complex resultant field.
Science Concepts Learned
Magnetic Fields
Two magnetic fields in the same space combine into one resultant field. A bar magnet's field collides with the Earth's magnetic field, and in some spots the two fields add together. In others they cancel completely, creating dead zones where a compass needle spins freely because no net force acts on it. You reveal this by placing a bar magnet on butcher paper and tracing the compass direction at dozens of locations around it. Connecting those points maps the curved field lines — and marks the null points where the two fields are equal and opposite.
Method & Materials
You will use a compass to determine the direction of a magnetic field at any point in space, explain how two magnetic fields combine, and predict the location of areas where two fields can cancel each other to leave no resultant field.
You will need weak to moderate strength bar magnets, very small compasses, and butcher paper.
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See what’s includedResults
Through this project, you'll be able to observe how two magnetic fields combine and predict the location of areas where two fields can cancel each other to leave no resultant field. This phenomenon is known as a "Bermuda Triangle".
Why do this project?
This science project is so interesting and unique because it allows students to explore the invisible magnetic fields around a bar magnet and the Earth, and to observe how they interact with each other.
Also Consider
Experiment variations to consider include using different strengths of bar magnets and different sizes of compasses.
Full project details
Additional information and source material for this project are available below.Related video
These videos explain the science behind this project and demonstrate key concepts used in the experiment.
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