How To Make a Compass - Emily's Science Lab

All compasses are wrong and today we will learn why with my experiment DIY compass. Hi everyone, I'm Emily Calandrelli, MIT engineer and host of Emily's Wonder Lab and on my channel we learn about all things space and science. So grab your needles and your magnets because we're about to find true north. For this one you need a bowl of water, leaves that will float on top of water, a single sewing needle, and a magnet. I have a stack of magnets here but you really just need one strong magnet. What you want to do first is fill your bowl with water and find a leaf that will float on top of it. Perfect. And our sewing needle is going to become our compass but let's see what happens when we just place it on the leaf. Nothing, right? Because our sewing needle is not a compass just yet. So get your sewing needle out and we are going to transform this sewing needle into a magnet which is going to become our compass. But how do we do that? Well our sewing needle is something known as ferromagnetic which means it's attracted to a magnet. Inside that sewing needle is a bunch of spinning electrons that each have their own north and south magnetic poles. But here's the thing, those electrons are all spinning in different directions so you don't notice their magnetic effect. But we can use a magnet to line up all of those electrons so that all of their north poles and all of their south poles are aligned creating a temporary magnet with our sewing needle. So what you want to do is take your magnet and parents and adults be very careful with magnets with little fingers they can pinch and you want to keep them away from electronics as well. If you know which end is your north pole you can rub the tip of your sewing needle with your north pole. I don't know which one is which here so I'm just going to choose this end. And you just want to rub your sewing needle like this. Just do that over and over and over again from the bottom of the sewing needle to the top. And what this is doing is it's aligning all of those spinning electrons to stand to attention in a single direction so that all of their north poles and all of their south poles are aligned. Once you've done that about 20 to 30 times we are going to place our sewing needle back on our leaf and put your magnet far away from the bowl and now just place your leaf back in the bowl. Now what's happening here? I can see the leaf moving. Let's see what happens when we move the leaf back this way. It's spinning. It's spinning. I can see it spinning. Now which way is it going? Okay and now it's stopped. So it's it's pointed this way and this way. Let's see if we move it around again just like that if it changes. Now look it's spinning to align itself back in this direction. In this general direction. So let's get our compass back out and see that is perfectly aligned with the north and south pole. So we have created a magnet with our needle. The eye of the needle is pointing north and then the pointy end of the sewing needle is pointing south. But it will spin. Watch it spinning. Do you see it spinning? There it goes, there it goes, there it goes, there it goes, there it goes. And it's going to stop around here and align itself with the north and south poles. Just I mean look at that. Exactly. We have created a compass with a needle and a magnet. How cool is that? Now this is so affected by magnetic fields. Watch what happens when I bring the magnet closer to our needle. Watch what happens. Look at it spinning. Look at that. Are you kidding me? Look how incredible that is. Whoa! We can just make our little compass like a boat. And you can also see it's affecting the compass as well. So the compass is pointing north this way but then when I move the magnet closer it doesn't know which way to go. Isn't that incredible that this can be impacted by something that is invisible to our eye. Magnetic fields that we don't even notice or see but it has such an impact. So I told you if you knew the north pole of your magnet you could swipe up to the pointy end and that would create the north pole of your needle at the pointy end and that would point to Earth's north pole. But you might say I thought light charges repel so why would the north pole of our magnet point to the north pole of Earth? Well here's why. Earth's magnetic pole is actually opposite of Earth's geographic pole. So Earth's true north is actually our magnetic south and our south pole is actually the magnetic north. So it's a little bit confusing but the north end of your magnet points to the north pole. But here's another wrench for you. The Earth's magnetic pole and the Earth's geographic poles are just shifted 10 degrees. They don't line up perfectly. And so Earth's geographic pole is 10 degrees different than Earth's magnetic pole. And because of this all compasses are wrong. They're still useful because they're still pointing in the general direction of north but they're all about 10 degrees off. Thanks for making a DIY magnet with me. If you like this one be sure to check out my best-selling Stay Curious and Keep Exploring book series for 99 more science experiments. I'm Emily Calandrelli. Subscribe for all things science and space and remember stay curious and keep exploring. I'll see you next time.