Can Openers Made of Aluminum?

I have a bag that I carry to work with me daily, and have for weeks. In this bag, I carry a handheld can opener (made from aluminum). There were also some loose aluminum paper clips scattered in the bottom of my bag. Today, I opened the bag and found that somehow the can opener has been magnetized, and lifts up small metal objects easily. How could this happen by chance, just carring the bag to and from work daily?
- Michael (age 26)
Baltimore, MD

Hi Michael

No self respecting piece of aluminum would attract a paper clip or vice-versa.

I have never seen a can opener made of aluminum.   I suspect you haven't either.

 

LeeH

(published on 10/02/2014)

I googled the model of can opener I have, and you're right that it turns out to be made of steel, not aluminum. I'm still curious though how it could have become magnetized to pick up paper clips.
- Michael (age 26)
Baltimore, MD

Hi Michael,

Certain steels, especially those with a high carbon content, can easily be weakly magnetized by giving them a sharp mechanical blow in the presence of another magnetic field, even the earth's magnetic field.  The blow allows the little domains in the steel to rattle around a bit and then settle down pointing in the direction of the external field. The resultant magnetism is fairly weak but strong enough to attract a paper clip or two.

 

LeeH

(published on 10/03/2014)