Sirius Zero: Building A Corporate Kingdom After Being Expelled

Chapter 164 - 164: A lesson in metallurgy

"Mikaela, here you go. And pay attention to the notes," said Maria, handing Mikaela her grade assignment.Mikaela looked at the C-grade, but then saw a small note in Maria's neat handwriting.

"Very well done. 8 out of 10 correct. I've marked them as such," said the note.

Mikaela scanned through the answers.

Sure enough, there were tick marks on eight out of the ten problems, with the remaining two having notes about where she had made mistakes.

With a small thrill of satisfaction, she put the assignment away.

"Ms. Washington? What's with these notes?" asked Anna.

"Those notes are to help you learn for next time," said Maria.

"OK," said Anna, though she seemed uncertain.

"Now class, we start with a new science topic. Specifically, about metals," said Maria, and cleared the whiteboard.

"First, can anybody tell me what defines a metal?" she asked, turning back to face the class.

"Screamin' an' distortion guitars," piped up a boy, which earned him a bout of laughter.

"That's probably true for music, and not the actual material," chuckled Maria.

"They get hot fast?" said a girl uncertainly.

"OK, yes, they conduct heat and electricity," said Maria, writing it down on the whiteboard.

"They can be hammered into shapes to make stuff," said another boy.

"Yes, that's called malleability. The physical property that allows a metal to be beaten into sheets," said Maria, noting it down.

"They shine? Not like a diamond, but they can still reflect light," said Mikaela.

"Yes, that is called luster, they can shine in light, especially when pure and polished," said Maria.

"So how is it different from a diamond sparkle?" asked Anna.

"Well, both diamond and metals have something in common, they have what is called a crystalline structure. The difference, is that diamonds have a much larger crystal structure than most metals, so when light enters a diamond, it has more room to bounce around which gives you that signature sparkle. Metals on the other hand, have a crystal structure that is so small, that light doesn't bounce around inside it. However, that also means that if you polish a metal, it can reflect light so smoothly that you get a mirror," said Maria, drawing sketches on the whiteboard to show the difference.

"Now aside from these common physical properties, metals also have a property called ductility. They can be stretched or drawn out into wires and rods without completely breaking. Those are physical properties, but what really makes metals, are their chemical properties, or how they react with other materials and elements. First, is oxidation. All metals can react with oxygen in the air, some more so than others. An everyday example of this is rust. The second is called corrosion, this is when metals react with an acid and they form a salt. The table salt you eat is an everyday example of a metal called Sodium reacting with an acid to form a salt called Sodium Chloride," explained Maria.

"Why doesn't gold rust?" asked a boy.

"Gold doesn't rust because it takes a lot of work to make oxygen react with it. How easily a metal, or any element reacts with another, is called reactivity. Gold, and other metals that have been known since ancient times have lower reactivity than others. Iron for example rusts, but if you stick it inside a charcoal furnace, it can be recast almost good as new," said Maria.

"What about stainless steel?" asked Mikaela.

"Stainless steel isn't actually a pure metal. It is what is known as an alloy, or a mixture of a metal with other elements or even metals. To get stainless steel, you mix iron with carbon and chromium, and in the case of stuff used in the kitchen, even nickel. Because all of these metals and elements have different reactivity, as well as different properties, they change what the main metal usually does. Chromium, aside from adding more shine, forms a microscopic layer of chromium oxide which protects the iron from reacting with oxygen and forming rust, even when the layer is scratched. Nickel isn't as reactive, so it stops food acids like vinegar from corroding the iron. And carbon, well, carbon makes the metal harder so it's easier to for the alloy to stay in shape instead of bending or warping, even when heated," said Maria.

"What about titanium? I've heard that it is super-expensive to use," asked Mikaela.

"Yes, because Titanium has a nasty habit of reacting with oxygen. At room temperature, this is a good thing, because it forms a thin layer of titanium oxide that stops the rest of the metal from rusting or corroding, but if you heat it, then it starts to react faster and grab more oxygen from the air, so instead of a soft or molten metal that you can cast and work with, you end up with a brittle piece of oxidized titanium that shatters into a powder. On the other hand, if you heat up iron, you can hammer it and work it while it is red-hot, right in the open air. So that's why titanium is so expensive to work with. You need special gas chambers and tools to actually turn raw titanium into usable parts," said Maria.

"And why does the SZPD use tungsten for their bullets?" asked Mikaela, eliciting whispers and stares at the mention of the SZPD.

"Well, that's because of Tungsten's unique properties. It is very dense - far denser than steel or even lead, and it is extremely hard, so military forces and the SZPD use it to make bullets that can punch through the thick steel plates of a tank," said Maria, wondering about Mikaela's interest in metals.

Just then, the bell rang, signalling the end of class.

"OK, we'll pick this up tomorrow," said Maria, as the fifth grade students filed out.

---

"You seem to be chipper," remarked Annette, as she drove home with Mikaela in the back seat.

"We had an interesting science class today," said Mikaela.

"Oh?" asked Annette.

"Yup, learned about metals. Did you know that titanium requires a special gas chamber to work with, and if you try to heat it up to melt of forge in the open air, it turns into brittle powder?" asked Mikaela.

"No, I didn't know that," said Annette.

"And did you know that tungsten is so dense that bullets made from it can punch right through steel?" asked Mikaela.

"Yes, that I'm all too familiar with," ground out Annette.

"Did you know that tungsten is actually extremely expensive and difficult to mine? And yet, the SZPD uses it for all its ammo, and the St. Ignatius uniform actually uses tungsten nanowires to prevent rips?" asked Mikaela, as she looked through the information she had collected on her phone.

"So? What are you saying?" asked Annette, with a bite of impatience.

"Just saying it's a cool fact," said Mikaela.

"Yes, well, that's not worth blowing thirty grand over, so drop it," snapped Annette as they arrived at the house.