Understanding Magnet Myths & Facts

By Shalea Hardison

When it comes to magnets, there’s a lot of information and misinformation out there.  And it can be hard to separate fact from fiction. Here are the top five magnet myths we find ourselves explaining regularly.

1. Magnets erase your hard drive.

To explain this, it’s important to note there are two types of drives: solid-state drives and hard disk drives.  Traditionally, hard disk drives (HDD) create binary code by changing the polarity of the magnetic bits. So, in theory, a magnet would flip the bits and effectively erase any data stored on the HDD. Unfortunately, the strength of the magnet needed to accomplish this feat is equal or greater to that of most MRI magnets, or 1.1 Tesla. Solid state drives (SSD), for example, USB thumb drives, smartphone memory, and some laptops keep binary code in a stored charge. No magnetic field is needed.  In this case, a magnet poses no ability to affect the stored data on SSDs.

It’s a magnet myth.

2. You can order a monopole magnet.

If we remember our science classes, we recall all magnets have a north and south pole. If you cut a magnet in half, you simply have a smaller magnet with two poles. These are called dipole magnets and is how magnetic material is found naturally. While we manufacture magnets with more than two poles (flexible magnetic sheeting commonly is magnetized this way), it isn’t currently possible to provide a magnet with just one pole.

Confusion over single pole, or monopole, magnets stem from multiple sources. First, some magnets are sold labeled as north or south – which isn’t to say they are monopoles. These magnets simply have a particular pole facing out, with the opposite pole covered with adhesive or surrounded by a metal or plastic cup. Some applications require a north/south magnetic selection, where it is important to match the poles correctly. 

Another reason for confusion stems from marketing terminology. A Google search for "monopole magnet for sale"’ yields upwards of 247,000 results. None of these magnets are actually monopole magnets. Rather, they are the same magnets and magnetic assemblies sold as basic dipole magnets.

However, recent groundbreaking research led physicists to create a synthetic magnetic monopole under extreme conditions in a laboratory*.  This paves the way for future potential breakthroughs, despite the fact that no observation of a naturally occurring magnetic monopole has been identified.

It’s magnet myth – for now.

3. Magnets are positive/negative.

If you think of a traditional image of a bar magnet, half red and half blue, then it might be easy to understand why some people interpret the north and south poles as positive and negative. In reality, permanent magnets don’t have a positive or negative charge. They have two consistent magnetic fields or dipoles. Currently, there are no monopole magnets. By nature, an electrical charge is either positive or negative and can exist without its opposite. Because an electrical charge is referred to as a monopole and magnets cannot be monopoles, positive and negative magnets don’t exist either.

It’s a magnet myth. 

4. Magnets will damage my cell phone.

In this case, it’s mostly a myth. We can refer to our first myth for science (magnets won’t damage the phone’s memory). However, magnets have the potential to impair the phone’s internal compass. Fortunately, most magnets simply aren’t strong enough to cause a problem – even neodymium magnets. It takes a larger rare earth magnet to interfere with the internal magnetic sensors or to lightly magnetize internal steel components. Just think about how many cell phone cases, holders and accessories feature magnets to understand how confidently magnets are used near cell phones. However, since we love our maps and apps, we don’t recommend rubbing industrial-strength magnets all over your phone!

It’s mostly a magnet myth.

5. Keep magnets away from credit cards, gift cards, and hotel keys. 

This is one magnetic fact that is rapidly changing with time. The black stripe on the back of most cards is referred to as a magnetic stripe. So it’s logical that the stripe can be erased, or even partially scrambled, by coming in contact with a magnet. However, not all magnetic stripes are created equal. The coercivity of a typical credit card is high, meaning it takes a little more work to demagnetize the strip. Hotel keys possess a lower coercivity meaning making them much more susceptible to demagnetization. However, with the advent of RFID chips, magnetic strips soon may be irrelevant. Permanent magnets have no effect on RFID chips. They won’t erase, block or scramble the card’s data.

It’s a magnet fact – for now.

While many of our old magnetic beliefs stem from the days of old technology, like CRT and floppy disks, others failed to keep up with cutting-edge research. Turn to our Magnet Experts for help deciphering any magnet myths you run across.

*https://phys.org/news/2014-01-physicists-synthetic-magnetic-monopole-years.html