Focus on Lenz’s Law

photo copy 2by: Ted Beyer

Ahhh, Eddy Current Tubes – you would never think that a hunk of copper pipe and a magnet could make anyone grin from ear to ear. I just love these things. So simple in appearance, and yet so magical to see and use. Whenever I happen to have a set at home, I soon lose control of them to my wife who is just as fascinated by them as I am.ed100_2 2

Although they can be used in fairly high end physics demonstrations, they are stunning enough that everyone who has a chance to see them is simply amazed.

Just realized – you may not have not seen one, have you? Here’s a video for you:

Kinda cool, huh? So, since I have (hopefully) gotten you to say “wow,” I’ll just bet you are wondering “why” — here’s some science:

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Iron Filings Exploration

Michelle Bertkeby:  Michelle Bertke

Simple iron filings can be used for a variety of interesting experiments and demonstrations.  Magnetism is a mysterious concept that can be difficult for students to grasp.  Magnetic fields are the forces surrounding a magnet that are identified by how they interact with adjacent magnets and other metal objects.  While magnetic fields are ‘invisible’ they can be observed by sprinkling iron filings on a white paper with magnets beneath.  Iron Filings

By lightly coating the surface of the paper, the magnetic field will appear as filings align themselves with the field.  Different magnets, depending on their strength and shape will create varying patterns in the iron filings.  A bar magnet with a distinct north and south will show characteristic lines of a magnetic field.  Circular magnets may show multiple lines indicating multiple magnet fields.  The stronger neodymium magnets will cause the iron filings to pile up in spikes due to the increased strength. This demonstration can lead to a discussion about magnetic fields: What they are, Where they can be found, and How they are used in the world around us. Read the rest of this entry »

Earth’s Magnetic Field

Martin Sagendorfby:  Martin Sagendorf

We recognize heat & cold, dry & damp, light & dark, and sound & silence.  However… I find it absolutely fascinating to consider that we also live within something that we can’t see, hear, touch, or taste.

We all Know:

Our planet has a giant magnet near its core and that its field extends over the whole of the Earth’s surface.  But, do we ever really think about this field that passes through soil, rocks, buildings… and us? Granted, relatively speaking this ‘field’ isn’t particularly strong.  In fact, it’s a rather weak field when compared to those of a horseshoe magnet or, particularly, a modern Rare Earth magnet.

A Great Demo to show Earth’s Magnetic Field:

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