Remember, there are four different kinds of forces: strong nuclear force,
electromagnetism, weak nuclear force, and gravity. There are also four basic force fields that you come into contact with all the time. They are the gravitational field, the electric field, the magnetic field, and the electromagnetic field. Notice that those four force fields really only use two of the four different kinds of force: electromagnetism and gravity. Let’s take a quick look at what causes these four fields and what kind of objects they can affect, starting with the magnetic field.
Here’s what you need:
Please login or register to read the rest of this content.
I noticed that as you were swiping your magnet on your needle, the compass was spinning like crazy, is that because of the magnet?
Sure, feel free to use a piece of cork. But there is no need for tape. Just stick your magnetized needle through the cork.
Could I use a cork and tape?
Magnetic poles are the two points of a magnet from which lines of magnetic force are directed. The rotation of Earth’s molten iron core creates the magnetic field. The material in the Earth’s core is hottest closest to the center, but cools as it moves outward. Convection causes this molten material to flow in and out of the core…which causes it to heat and cool. As the material heats and cools, it creates twists and turns in the magnetic field. These irregularities cause changes in the Earth’s magnetic field. The magnetic north and south poles are only “slightly” shifted to the same side of the globe. But they are still very close to the north and south spin axis of the Earth.
Why are the north and south polls on the same side? And why are they moving, or what’s causing them to move? And did they move to the side like that?
Yes, it sounds like static could be the issue. Try using a bowl made of glass. Also, in the video, we mention using a small container so the foam/cork isn’t floating all over the place. However, feel free to try the experiment in a larger container or even a sink or bathtub. You only need the water level to be high enough for the foam/cork to float.
Our experiment mostly failed. We tried large cork, then cut it smaller, then realized that even without the metal rod, the cork was attracted to the edge of the ceramic bowl. Is this possible static electricity interfering with the magnetic force?
The magnetic field is one of the forces. Gravitation is another force.
what are the forces in a magnetic field
It depends – you do need to swipe all in one direction to magnetize it.
don’t you have to re swipe the needle every once in a while
Thanks!
It sounds like the magnetic field is not very strong. Have you attempted to magnetize it a bit more? Be sure you’re running the magnet along it in the same direction every time.
I also have one needle that is only attracted to other magnetized needles, but never repelled. Why is that?
Sometimes needles are hard to de-magnetize because they are so small and lightweight. If you are able to smack it a few times hard with a non0metal object (so it doesn’t stick to it), you might have more luck. Rubbing the needle both ways will jumble up the domains inside as well.
I tried dropping the needles to jumble up the iron atoms, but they still magnetized to each other.
Also, why would rubbing the magnet on the needle in both directions not work?
Thank you Aurora!
The compass is reacting to the magnet because it’s so close to it. The compass itself is magnetic. Normally the needle would simply line up north and south in alignment with the Earth’s North and South Poles. However, getting the magnet so close to the compass means that it has a bit stronger of a magnetic pull than the Earth due to its proximity. So you see the reaction – the compass doesn’t quite know where to point while it tries to align with the nearby magnetic field that is in constant motion.
why was the compass going crazy when you were rubbing the needle? Daniel A. Earnest
We experienced the same phenomenon as Robert D’Angelo, and we experimented like he did. I moved the magnets completely out of the room. And the needle in the foam was still attracted to the sides of the bowls (different materials). It also didn’t consistently go to one side of the bowl or the other. It appeared as though the foam or needle were attracted to the bowl. We added more and less water too. Same thing. Could it be static electricity in the foam?
sooo much fun…. the best part is it accualy works. such a good idea fo a campout in the woods
The water allows the cork to move so the needle can align itself with the magnetic field we live in everyday (but don’t really notice) from the Earth. Water has very low friction, so we use it to float the cork. Does that help?
y do u use water what are the forces?
Sometimes if your bowl isn’t large enough it can be hard for the water to settle enough without affecting the magnet. You should clearly see the needle rotate with a strong enough magnet influencing it. What happens if you try magnetizing it again(make sure you’re only stroking the needle in one direction only).
Aurora — We are stumped. We don’t understand why our needle and foam compass worked at first, but then was being dragged away from the middle of the bowl and then stuck to the sides with nothing obvious to attract it. We tried it with both a glass and plastic bowl.
Anderene D’
The magnet is influencing the compass, so when the magnet moves, so does the compass needle. The magnetic field extends beyond the magnet itself, so even if you can’t see the magnetic field, you can detect it’s there.
Hi Aurora,
I just watched the “Detecting the Magnetic Field” and I noticed that when you are rubbing the magnet against the needle, the compass in the lower-right-hand-corner is going berserk: The needle is moving around like crazy. Why?
Thanks
Try magnetizing it again to see if that makes a difference. Also, be sure to keep it away from metal or magnetic objects, because that will also affect how it works. Keep trying! A good scientist also has a sharp eye and sees things that most people miss.
mine’s not really working it keeps moving in a circle slowly and it’s not pointing north or maybe it is
I do not get it?????????????????????????????????
if you look at the compass it will move with the magnet it is really cool
No problem – that’s what I am here for! 🙂 Location of Compass refers to where you are in the room. For example: “in the doorway”, “by window”, “under table”, etc. and the direction indication is getting you to notice that no matter where you want or how to turn the compass, the needle always points in the same direction. If you prefer, you can edit the second column and state the object that the needle is pointing to with each new spot you test out. For example, if the needle always points toward the couch, then you’d write that in. (By the way, which direction would the couch be in if this were true?)
Hello – I am not quite sure what we are supposed to record with the student worksheet under “location of compass” and “direction indication?” Can you explain? Thanks!
Not sure if someone else has mentioned/experienced this, but we didn’t have the type of foam in the video so we used polystyrene foam I cut out of something else I had. We found that the needles kept gravitating to the sides of the cups regardless of whether it was glass, ceramic or plastic. We soon realised that somehow the polystyrene was “clinging” to the sides of the cup and was affecting the needles natural tendencies to head north!! Ended up using a thick foam sticker that floated and did as the needle wanted not what the polystyrene wanted!
Hi Aurora,
I am Tasha and did the”detecting Magnetic Field” experiment with my brother. I want to know why you have to rub the needle only one way on the magnet. I rubbed it both ways and it worked as well. I even tried doing it twice and it still pointed north.
Are you referring to the way the water moves a little? If so, then you’re right – you want the water to settle before taking a reading with your compass.
How can you tell between the movement of the water, and the magnetic field?
this is really cool! by the way this is Mia
Wow! Earth has a HUGE magnetosphere! Thanks!
Most hand compasses are magnetic compasses, which line up with the earth’s magnetic field to point to the magnetic north (they actually don’t point straight to the North Pole, but rather a spot in northern Canada). If you took a compass in a spacecraft orbiting the earth, its needle would point along a much bigger magnetic field that surrounds the earth called the magnetosphere. If the astronaut took it into deeper space outside of the earth’s magnetic field, the compass would only work when close enough to another object with a magnetic field: say an asteroid with magnetic minerals, or another planet. Here is a picture of what the earth’s magnetosphere looks like.
What would a compass point to if astronauts took one into space? Would it still point to the North Pole? Thank you!
“Pole” refers to the end of a magnet to and from which you can find magnetic force field lines. Every magnet has a north and south pole. North and north don’t like each other and are repelled when you face each other, but north and south poles are attracted to each other. Does that help, or did you have a different question?
I was reading about detecting magnetic fields.Could you explain what you mean about the poles facing each other and the others not.
Thanks
I asked our chemistry team your question, and here’s the response:
“A magnetic object has the ability to be attracted to a magnet or the ability to attract objects to it. Magnetism is the force of the magnetic field generated by an object that will attract a magnetic object to it. All metallic objects that attract other metallic objects generate a magnetic field. In order to become magnetized, an object must have an electronic structure that allows for charge alignment. So, any metallic object that is attracted to a magnet can become a magnetic itself, although the magnetic field could last a moment, or range all the way to permanence. A needle is stainless steel, but is not a high grade stainless…therefore, there is an abundance of carbon in its structure. A magnet stroked along a piece of metal will align iron atoms with their charges in a certain direction, with the positive charges aligned in one direction and the negative charges aligned in another direction. Different metals and metal alloys have differing amounts or iron, or ferromagnetic particles in them. If the electrons cannot be aligned in one direction, the metal is not magnetic. The needle that was magnetized exhibited ferromagnetism when the charges were aligned. Permanent magnets so strongly align in one direction that the alignment will be much more stable than with other materials.
“Several years ago, there was much hub-bub about rapid cataclysmic pole shifting. This shift was to be followed or concurrent with tremendous storms, floods, and earthquakes. The north and south poles have actually shifted completely numerous times. Modern scientific theory of pole shift has been called true polar wander. Scientists believe that any wander in the position of magnetic north or south has occurred over a much longer time scale that previously theorized. It is now believed that polar wander has never been larger than 50 degrees, and most of the time no more than 30 degrees. So, California will never become a magnet… sadly!”
Why is it that aluminum cannot be magnetic, but iron can? Would a look at the periodic table help to predict whether or not a metal is magnetic?
Great questions! I go into a lot of detail about what’s magnetic, what a magnetic field is, and how those fields interact. You’ll want to look into Unit 11, which is entirely about magnetism, but I’ll try to answer your questions here:
Electrons can have a “left” or “right” spin in addition to ‘going around’ the nucleus. Electrons technically don’t orbit the core of an atom. They pop in and pop out of existence. Electrons do tend to stay at a certain distance from a nucleus. This area that the electron tends to stay in is called a shell. The electrons move so fast around the shell that the shell forms a balloon like ball around the nucleus.
Magnetism is caused by moving electrons. Electricity is moving electrons. Electricity causes magnetism. Moving magnetic fields can cause electrons to move. Electricity can be caused by a moving magnetic fields.
When you asked “What’s a magnetic field?” Well, I can’t tell you. To be honest, nobody can. Magnetic fields, gravitational fields, electric fields are very mysterious and at this point there are still lots of questions about each one. But here’s what we do know:
A field is an area around a electrical, magnetic or gravitational source that will create a force on another electrical, magnetic or gravitational source that comes within the reach of the field. In fields, the closer something gets to the source of the field, the stronger the force of the field gets. This is called the inverse square law.
Magnetic fields are created by electrons moving in the same direction. A magnetic field must come from a north pole of a magnet and go to a south pole of a magnet (or atoms that have turned to the magnetic field.) Iron and a few other types of atoms will turn to align themselves with the magnetic field. Compasses turn with the force of the magnetic field.
If an object is filled with atoms that have an abundance of electrons spinning in the same direction, and if those atoms are lined up in the same direction, that object will have a magnetic force.
When you magnetized the needle, you actually twisted and turned atoms! As you moved the permanent magnet over the nail the iron atoms in the nail actually turned, to align themselves with the magnetic field of the magnet. Once enough iron atoms turned the nail itself became a magnet! Now let’s destroy the magnetized needle and turn it back into a regular old needle. When you drop it on a hard surface, you take atoms that were all nicely lined up and messed them up so they pointed in different directions. Since they weren’t lined up as nicely anymore they had much less or perhaps no magnetic force. CRASH! They get all jumbled up.
The geographic poles are located at the axis of the Earth. The axis is where the Earth turns day after day. Like the top and bottom of a toy top. The magnetic poles are close to the geographic poles but they are off by quite a bit. (The south pole isn’t even in Antarctica – it’s in the ocean.) In fact, the north and south magnetic poles of the Earth move from year to year and have completely flipped a couple of times! The reason they move is because the Earth’s core is not a solid chunk of metal – is a spinning metallic liquid, which creates the Earth’s magnetic field.
Whew – sorry for the long answer, but I hope this helps! 🙂
After having done this experiment and watched the video, I have questions about two subjects : 1)I’m a little confused about magnetic fields and being “magnetic”. Is this the same thing? In other words, do all “magnetic” objects have a magnetic field and are all objects with a magnetic field “magnetic”? We made the compass by swiping the needle with the magnet. Can you swipe anything with a magnet and have it become magnetized like the needle or does it have to be made of some special material (like the iron, nickel, cobalt you mentioned)? What is a needle made of? 2)In your video you mentioned that the magnetic north and south poles have moved over time. Does this mean that eventually the magnetic north could actually be, say over California and our compasses wouldn’t really give us a true north reading anymore? Also, what will happen if the two poles get too close together?
The strong and weak forces come into play with the atoms themselves. The strong forces holes the stuff inside the proton and neutron together (more about this in Unit 7) and the weak force has to do with radioactive decay of subatomic particles (college-level material, really). But if you really want an example of this force to share with your kids, it’s the weak force that starts the hydrogen fusion process in stars.
You mentioned that there are four forces, yet we come into contact with two? gravity and magnetic? What of the strong and weak nuclear forces? how do these play a role?
This was very interesting i like it – Tara daughter of Linda Usita
You’re right – and I think it has more to do with the landscape orientation of the paper than anything else. Since there’s no official orientation, just rotate your paper and now the solar system is vertical. 🙂 Since astronomers use spherical coordinates (ascension and declination) there’s no ‘right-side-up’ in their coordinate system either. It’s just a convention to place the north pole of a planet at the top of the page.
why isn’t the solar system ever shown vertically, instead of horizontally?
Haha… I just noticed that edit when you mentioned it. Good thing the laws of physics are still at work, even when we’re not paying attention! 🙂
My kids loved watching the reaction of the compass in the right corner of the the video as you rubbged the magnet on the needle. They laughed throughout the video.
Hahaha—- wait until we get to making the linear accelerators… he won’t be able to tear himself away for HOURS….
my 1st grader was most interested in turning the needle to the magnet he kept holding up to our home made compass… stinker. Magnets are great boy distractions! 🙂