Science Buddies: "Ask an Expert"

I am doing a science fair experiment with magnets. I am putting the magnets in boiling water, freezing water, and dry ice to see how temperature affects their strength. Some web sites recommend using neodynium magnets for this kind of experiment, and some say to use permanent iron magnets. Can you suggest which type of magnet to use? I would like to use the type that is most affected by temperature so my results will be as clear as possible. Thank you.

Hello houran123,

That sounds like a really great project! I cannot offer a suggestion for which one would be better, but have you thought about using both types of magnet and comparing the results afterwards to see which magnet is the most affected? You could have both types of magnet undergo the exact same conditions (boiling water, cold water, and dry ice), test their strength, and then compare the results to determine which type of magnet was most affected by each condition.

Good luck with your project and let us know if you have any more questions!

Best,
Kerri

Hello houran123,

Great project idea! I found a project on this site, is this the one you are doing? https://www.sciencebuddies.org/science- ... #materials. If so, they recommend using permanent iron magnets. From what I have read, Neodymium (also known as: neodymium-iron-boron, or NIB, for short) magnets are permanent magnets (one that creates its own magnetic field) and very strong due to the electron alignment (read the wikipedia article below on magnets), Iron magnets are also permanent magnets (read the Wikipedia "magnet" article below). Also, there is good information in the "background" section of this Science Buddies project. Kerri has a good idea to compare both iron and neodymium magnets--this would make for a more advanced project!

It sounds like you have done a bit of research yourself and that's great. I found some other articles that may help you in your research:
There is a nice chart on this page that shows the strength (remenance) of different magnets. http://en.wikipedia.org/wiki/Neodymium_magnet
http://www.mceproducts.com/knowledge-ba ... /28/28/1/2
Here is one that specifically talks about temperature: http://www.sv.vt.edu/classes/MSE2094_No ... eodym.html; also: http://en.wikipedia.org/wiki/Magnet
This article may be helpful in learning about how temperature affects magnets, and which are the strongest. Curie temperature is the temperature in which the dipoles of the magnet reverse direction. The information is a bit technical, so ask us questions. Basically, just know what Curie temperature is: http://en.wikipedia.org/wiki/Curie_temperature

So knowing that neodymium magnets are stronger than iron ones (and you know why now, after reading the above articles), that might affect your decision on which to choose, if you only choose one.

Please let us know how your project is coming along, and post here again if you have more questions.