![]() Electrons moving along a wire make a magnetic field that goes in circles around the wire. Moving electrons always create a magnetic field. I'll skip the details, but the calculations are all in this Python code.In this activity, students learn about the relationship between electricity and magnetism by creating and experimenting with their very own electromagnet.Īfter making the magnet, they can explore how it works by making modifications to the number of batteries, the length of wire and number of loops, and the type of core used.Įlectricity and magnetism are linked phenomena. In that case, I can use the magnetic dipole moment for a single iron atom and multiply it by the number of atoms in that carrot based on the molar mass of iron and Avagadro’s number. But let's just assume that under the presence of the magnetic field from the electromagnet all of its domains are aligned. In normal situations, it could have a zero magnetic moment if its magnetic domains aren't lined up. The magnetic moment for the carrot is a bit more difficult. ![]() Fortunately, I already have values for all of those quantities. For the electromagnet, the dipole moment depends on the number of loops of wire around the core, the circular cross-sectional area of the coil, and the electric current (in amps) running through the wires. The dipole moment basically is a way to describe the strength of a magnet, just like electric charge describes the strength of an electric interaction. The best way to describe both an electromagnet and a piece of iron is with a magnetic dipole moment (we use the symbol μ for this). Instead we have an electromagnet and an iron carrot. To make this cartoon situation even more complicated, we don't have two magnets. However, when the magnets get close, the force increases quite a bit. But if you have ever played with two magnets, then you should know that the attractive force is very weak when you are holding them far apart. I'll be honest, calculating how much a magnet can pick up is never very simple. As an equation, it looks like this:Ĭould This Electromagnet Really Grab an Iron Carrot? If we know the resistance of the electromagnet wire, then we can use Ohm's law to find the current. Resistance is a property that tells you how difficult it is to move electric charges through a wire, and it’s measured in ohms. To make a connection between voltage and current, we need to know the resistance. What does 10 billion volts even mean for an electromagnet? Remember, the most important thing about an electromagnet is the electric current (in amps), not the voltage (in volts). ![]() What about 1 million volts?" Someone else interjected: "Sure, 1 million volts is cool- but what about 10 billion volts?" It has to be over-the-top big." Another writer must have replied, "Let's put a number there. Surely someone raised their hand and said, "You know, we can't just do an electromagnet. Perhaps someone came up with the idea of an electromagnet and an iron carrot and everyone agreed to put that in there. I don't know how the script for this episode came about, but in my mind they had a group of writers working together. Coyote is assembling his contraption, we see that it comes in a huge crate labeled "One 10,000,000,000 Volt Electric Magnet Do It Yourself Kit.” ![]() It's such a simple and awesome plan, it just has to work, right?īut wait! Here's the part that I really like: While Wile E. Coyote will turn on a giant electromagnet and pull the rabbit right to him. After the carrot is consumed (and I have no idea how that would happen), Wile E. First, he's going to drop a carrot-shaped piece of iron into Bugs' rabbit hole. After a couple of failed attempts to capture Bugs, he comes up with a new plan. Coyote has decided he should eat the rabbit. The basic idea is, of course, that Wile E. Let me set the scene-and I don't think we have to worry about spoiler alerts since this episode is 60 years old. Coyote walk on two legs, talk, and build stuff. I like to analyze the physics of science fiction, and so I'm going to argue that the Merrie Melodies cartoon “ Compressed Hare” takes place in the far future when animals rule the world.
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