The Chemistry of Currency


Dr. Kenneth Lyle, Duke University Department of Chemistryby Gabrielle Hodgins and Dr. Kenneth Lyle, Duke University, Durham NC

The wonders of magnetic ink!

INTRODUCTION

Demonstrating the magnetic ink used in printing US currency has proven to engage audiences of all ages because of its relevance to everyday life.  Nearly everyone has used machines that distribute and/or accept currency but few understand how the machines distinguish between the various denominations.  The key is in the face of each denomination.  Magnetic ink is used in the printing of the currency.  Each denomination has a different face and, therefore, a different magnetic signature.  Similar to a bar code reader, the machines recognize the denomination by its magnetic signature.  A strong magnet, such as a neodymium magnet, can be used to demonstrate the magnetic character of US currency.

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Introducing the Home Science Lab!


donna_giachettiby:  Donna Giachetti

Albert Einstein famously said,

The important thing is not to stop questioning.
Curiosity has its own reason for existing.

At Educational Innovations, we agree wholeheartedly.  Our company was founded by a master teacher in 1994.  Today it’s still run by a dedicated crew of teachers who share a passion for science… and for fostering curiosity in kids.

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The Magnetic Accelerator


janice-cup-picture-ipgby Janice VanCleave

I love the magnetic accelerator. In fact, I met friends at a restaurant yesterday and took the accelerator with me. We had a lot of fun predicting what would happen and testing our predictions. No formal steps….just making cool guesses and then discovering whether we were correct.

Yes! The steel ball shot off the end of the track and hit the floor a couple of times, but that just added to the excitement.  It’s a small town and few are surprised that the eccentric science author is experimenting at the restaurant –again!Magnetic Accelerator

A parent came in with her daughter, a second grader. With the mother’s permission I invited the child to sit with us. The girl had sinus problems and didn’t feel well.  She was a bit sluggish and her eyes looked dull, as one would expect. When I asked the child if she wanted to do some science experiments, her dull eyes brightened. She had not been present during the previous testing of the accelerator, but she was immediately interested.

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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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Seeing a 3D Magnetic Field


Martin Sagendorfby: Martin Sagendorf

 

This 3D Magnetic Field demonstration is actually quite easy to do.  It clearly illustrates that magnetic fields are not flat (as too frequently demonstrated in the classroom).

Demonstrating a 3D Magnetic Field

This easy-to-make construction requires only four components:

  1. A clear plastic bottle (about 1-3/4” in one dimension) – the one illustrated below is a 12.6 fl oz ultra concentrated Joy ® dishwashing soap bottle – Note that any bottle originally containing soap or detergent will require repeated rinses to completely remove all of its original contents.3D Magnetic Field with Neodymium Magnets
  2. Six 17 mm x 3 mm Neodymium ring magnets Read the rest of this entry »