The Hidden Life of Magnets

Ainissa Ramirez is a Scientist, Author and a self-proclaimed “Science Evangelist.” She is the creator of a podcast series called “Science Underground.” She joins Hari Sreenivasan to discuss the hidden life of magnets.


Ainissa Ramirez is a scientist, author, a self-proclaimed 'science evangelist.'

She is the creator of a podcast series called 'Science Underground.'

She joins me now to discuss the hidden life of magnets.

You've got the magnet that we are all familiar with from elementary school...

Right, right.

...and cartoons.

[ Laughs ]

But then there's also magnets in our everyday lives that we're taking for granted.


That's right.

Well, first of all, Silicon Valley, before it was Silicon Valley, should've been 'Iron Oxide Valley' or 'Magnet Valley,' because one of the biggest businesses was hard disks.

So that's one of the first places where magnets have tremendously impacted our lives.


Today they're in your earbuds.

There's a magnet that makes it so that you have high fidelity.

But it's also in your money, and so I want to show that to you.

In our money?

In your money.

Okay, so now you're pulling out a super-duper magnet...

Super-duper magnet.

...that you can find at science hobbyist stores.

That's right.

And if I were to have this dollar hanging from a string -- because it's a very subtle effect -- if I bring this magnet across, you'll see something.

Oh! Whoa!

So there is, what, metal in our money?

So, within the ink are small particles of iron that will, you know, prevent you from making counterfeit money.


So there's sensors within, so when you're putting your dollar into a machine for a coke, if you will, it spits it out -- it's sensing a couple of things.

One of the things it's looking is for magnetization.


And there's magnets in our cellphones, and we kind of know when our computer screen goes a little fuzzy, right?

That's right.

They seem to be everywhere and yet kind of this quiet metal that --

It is. It's very understated.

But without magnets, a lot of us wouldn't be here, because this is how we traveled.

We used compasses.

It's based on magnetism.

The Earth is a magnet, by the way.

[ Both laugh ]

So, how has our relationship with magnetism and magnets changed over time?

As you said, obviously, the first explorers figured that out, that there were these magnetic poles and that we could actually navigate.

And now we've got cellphone manufacturers putting them in and electronics manufacturers that use them all the time.

It went from magic, you know, with the lodestone, a very early mineral that people walked by and they saw that things were stuck to it, and so it had some kind of majestic to it.

Then it became something that was useful when we used it as compasses, and now we don't really think very much about it.

We kind of take it for granted, because our computers have memory, but we don't really realize that a lot of that is due to magnetization, due to magnets.

And the magnetization in memory, explain that connection to us.

What makes a hard disk a magnet?

Well, that's a very good question.

That was also my dissertation, so thank you very much.

[ Laughs ] Didn't realize that.

But the hard disk actually has a thin layer of crushed iron particles -- you could think of it that way -- in a paste.

And above it is something that reads it.

It's an electromagnet, and it can sense the ones and zeroes, the north and south poles, and that's translated into a language which eventually becomes like the letter A on your screen.

So, wow.

That -- You're blowing my mind right now.

So, basically, in there, that hard-disk drive --

The hard disk, the thing that's spinning really, really fast, it has a thin layer of magnetic material, and those little north and south poles, that's the ones and zeroes.

And so that tiny little thing that's scanning a hard disk -- or if it's a solid-state disk, it's a different kind of thing?

That's right.

It's a different technology, yeah.

That's all it is, is we're just recording ones and zeroes, right?

It's sort of like a record player, yeah -- only instead of feeling vibrations like we did with the stylus, now we're just sensing ones and zeroes, north and south, and that's getting translated into data.

So if we didn't have the ability to read the ones and zeroes magnetically, we would have none of this?

We would have none of this.

And let me tell you, the first hard disk which was created by IBM -- or one of the commercial ones -- was RAMAC.

It was about half the size of a refrigerator, weighed about a ton.

You needed like four guys to push it into a truck.

Now if I want a package for a hard disk, it comes in a small box.

This required lots of people to put it onto a plane, and its memory was five megabytes.


That's right.

So it could hold a selfie of itself.

[ Laughs ] That's about it.

That's about it.

That's about it.


All right.

So, when we think of kind of the evolution here, what is the next frontier for magnets, magnetism, and how we use magnets?

Perhaps it's in space travel or perhaps it's in our electric cars.

Well, it's always gonna be fascinating to us, even from kids, like, 'How small can we make a magnet?'

And that translates to, 'How much memory can I put on a hard disk?'

So that's a question that people are always asking.

You never have a magnet that's only a north or only a south.

They always come in poles.

There's lots of physics behind that that people are very interested in.

How do magnets behave in different temperatures, under different pressures?

That's also very interesting from a geological point of view.

So magnets will always be fascinating.

They've got utility, but there's always folks who are always looking at how interesting they are, as well.

All right then.

Always magnetic, Ainissa Ramirez.

Thanks so much for joining us.

Thank you.