Alien in My Pocket (8 page)

Try It Yourself: Building Your Own Electromagnet

E
lectromagnets use a flow of electricity, called electric current, to produce magnetic fields. You're probably already familiar with magnetic fields since you can feel their effects, such as the pulling force a permanent magnet makes toward a ferromagnetic material—like the door of your refrigerator. Electromagnets are cool because you can vary how strong they are by making simple changes to their construction.

 

Y
OU WILL NEED
: a pencil-shaped piece of metal that a magnet can grab (like a bolt from the garage), insulated wire (the kind called “magnet wire” is the very best), a battery, and something to grab (like a handful of paper clips), and an adult to supervise.

 

Magnet Construction

1. Take the pencil-shaped piece of metal and start wrapping the insulated wire around it. Wind carefully to fit in lots of wraps. Leave about a 6" tail of wire sticking off each end so you can attach the leads to a battery.

 

2. Make sure the ends of the wire are stripped so you can attach the metal core to the battery. If you're using wire with plastic insulation on it, you will need the help of a parent to use a knife or wire strippers to expose the copper underneath. If you found some magnet wire, use sandpaper to remove the lacquer on the outside of the copper wire. It can be hard to see since it's clear.

 

3. Connect the wire ends to your battery. Voila! You should be able to attract a number of paper clips to the end of the metal piece, which is the electromagnet's core. Congratulations—you have built an electromagnet! You might not know it, but you're surrounded by electromagnets very similar to the one you just built. The closest ones might be inside the speakers of your TV or cell phone.

Experiment Time

1. What would it take to supercharge your electromagnet like Amp did for Zack? In the book, Amp intensifies Zack's electromagnet strength by concentrating extra magnetic fields through the magnet's core, which increased its grabbing power. You can do the same by intensifying the magnetic field going through the core of your own electromagnet. Do this by adding more wraps of wire onto your electromagnet. The more wraps you add, the more power the electric current can add to the magnetic field. The more power in the magnetic field you have, the stronger your magnet! How many wraps do you need to pick up twice as many paper clips as before? Try using a smaller-diameter wire to fit on more wraps, something between 20 and 28 gauge. For any wire, the higher the gauge number, the smaller the diameter.

 

2. Another way to intensify the magnetic field produced by your electromagnet is to increase the actual amount of electricity (aka
current
) going through all of your wire wraps. To increase the current, you need to “push” it harder by using a higher voltage. If you started with a normal AA battery, you were putting 1.5 volts onto the wire. You can push the electricity twice as hard by adding another battery in the series, giving the electricity 3 volts of pushing. By pushing twice as hard, you'll get double the current, which should roughly double the strength of your electromagnet!

 

3. In the book, Amp “guides” extra magnetic fields into Zack's electromagnet core. You can also guide the magnetic field produced by your electromagnet. Magnetic fields like to flow through some materials quite a bit, and other materials not so much. Air is not a magnetic field's favorite substance to flow through, especially compared to a ferromagnetic material like iron or steel. Find another pencil-shaped piece of iron or steel, like a bolt or a nail, and hold it at the end of your electromagnet while it's turned on. What happens at the end of the nail? It acts like a magnet itself, because you're using it to guide the magnetic field. Just like Amp does.

Notes About Safety

• Down at low voltages, electromagnets are pretty safe. But naturally, you're going to want to add more batteries to make your electromagnet more powerful. This is awesome, and you should do it. But be careful! When experimenting with more powerful batteries like 9-volts and beyond, make sure to have an adult supervising. And wear safety glasses in case you get a spark.

• You'll probably notice that when you run your electromagnet for a while, it gets hot. This is because most of the electricity from the battery is dissipated as heat by going through the electrical resistance of your wire. If you use bigger batteries, it's going to get hot faster. If you use really big batteries, you could burn yourself or even melt the insulation or the wire. Use caution and always start small.

Troubleshooting

• If your electromagnet doesn't seem to work, the usual culprits are either a dead battery, too small of a battery, or the most common problem: not making a connection between the wire and the battery in the first place. Ensure you have a good contact directly with the copper in your wire by carefully restripping the plastic insulation off the wire. If you used magnet wire, spend a little extra time sanding the insulative lacquer off the conductor to ensure a good contact.

Read a sneak peek of book three of the Alien in My Pocket series:
Radio Active

“I
t smells like the devil burped in here.”

Olivia had just shut the door of my room. She pulled two rolls of SweeTarts out of her pocket and tossed them to Amp, who was still sitting on my alarm clock.

“It smells like that because he keeps eating those fart pills,” I said, still hunched over my math homework. “Hey, did you get the one about the train leaving San Francisco at eight p.m.?” I asked, turning around in my chair.

Olivia is in my class at Reed School. Schoolwork isn't difficult for her. Olivia just sort of knows stuff. She usually finishes her math homework while everyone else is packing up to leave for the day. She'd be a real brain if she weren't so weird and didn't talk so much.

“Forty-eight miles an hour is the answer,” she said, watching Amp flip SweeTarts into his mouth.

“Forty-eight?” I croaked. “I have five hundred forty-four!”

“How is that possible?” She laughed, shaking her
head at me. “What train travels that fast, Whacky Zacky?”

“Maybe those Japanese bullet trains. I saw them on TV.”

“They don't go that fast,” she corrected me. “Two hundred miles an hour, tops.”

“We have trainlike vehicles back on Erde,” Amp said, once again bragging about how great things were on his planet. “They travel about as fast as sound travels here.”

“I've told you before about talking with your mouth full,” I grumbled, turning back to my incorrect math problem. “You may have fast trains on Erde, but we have something called manners here on this planet.”

“Has he been this grumpy the whole time?” Olivia asked Amp.

“Since he got home. Surprisingly, math makes him angry.”

Honestly, all our meetings about fixing Amp's busted spaceship, getting him off this planet, and returning my life to normal went like this. What was the point of meeting if we never accomplished anything except pointing out all the things I do wrong? I was so not the problem.

There was a knock on my bedroom door. Olivia quickly moved to block the view of Amp from the doorway.

She always did this, even though Amp could easily make himself invisible to someone. He uses one of his Jedi mind tricks. He basically erases your memory of seeing him as you see him, so you instantly forget you're seeing him while you're looking at him.

I know, it sounds complicated. You get used to it. But Olivia always forgets he can do that.

The door clicked open and my little brother poked his head in.

“I heard you have SweeTarts,” he said. “I want some.”

“Go away, Taylor,” I groaned from my desk. “We're busy.”

Olivia reached into her pocket and tossed Taylor a roll of SweeTarts. He intentionally missed the catch so he could step all the way into my room. “Hey, what are you guys doing?” he asked, looking around. “It smells like burning toothpaste in here.”

Taylor knew something was up. He knew I was hiding a secret, and he'd dedicated his life to figuring out what it was. He'd even built an army of spy robots to help him. Fortunately, I'd destroyed most of them when I caught them in my room.

My parents are convinced Taylor is some kind of genius. He
is
only in the first grade and building robots. But I don't care. I think he's only a genius at annoying me.

I got up and pushed him out of my room. “Go play with your robots, you Nosy Nelly.” I closed the door on him and leaned my back against it.

“But I want to hang out with you guys,” he said from the other side of the door.

“Buzz off!” I shouted. I heard him walk down the squeaky hallway.

Olivia sat up on my bed. She had an odd look on her face. It was almost white, like she'd seen a ghost.

“What's wrong with you?” I ask. “Is Amp's gas cloud getting to you?”

“How did he know I had SweeTarts? I didn't tell him, and you didn't tell him, so how did he know?”

The three of us stared at each other.

Without looking down, Olivia unclipped the walkie-talkie from her pocket. She held it up and stared at it. “That little sneak is listening in on our walkie-talkie conversations.”

“What a clever idea,” Amp whispered.

I looked at them both. I was pretty sure steam was coming out of my ears. “A clever idea that the little worm is gonna pay for.”

About the Author

NATE BALL
is the host of the Emmy and Peabody award-winning PBS reality shows
Design Squad
and
Design Squad Nation
. An MIT graduate with a Master's Degree in mechanical engineering, Nate is also the cofounder of Atlas Devices, a two-time All-American pole-vaulter, and a competitive beatboxer. He lives with his wife in Cambridge, Massachusetts.

 

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