Big Shark

In the last few months, John Stevens and I have been training teachers on Math and Technology in the classroom with Classroom Chef.

Things are good.

One of the lessons in La Cucina hasn’t been recorded here yet, so here we go.

Big Shark

Start class with the media, which I got from Timon Piccini.

All students: Whoaaaaa!

Here’s why this is an excellent 3-Act math task:
StudentsB immediatelyB start asking questions.

Alex: How tall is that lady?
Marie: Is that shark still alive?
Dylan: What’s her Mullet Ratio?
Mr. Vaudrey: Aw, you’re a sweetheart. What else?
Lorraine: Do any other organisms live in a symbiotic relationship with it?
Mr. Vaudrey: Wow. Ms Smith owes you a high-five for that one. What else?
Victor: Is that one shark or two jaws facing each other?
Alyssa: Is she standing, like, really far back to make it look bigger?
Luis: What does that shark eat?
Frankie: Is that a Megalodon?

To that question, I responded, “I dunno. What’s a Megalodon?”

Frankie then had the full attention of the class as he stood and described the giant prehistoric shark that is large enough to destroy boats and battle a giant octopus. He was crushed to find out that the Megalodon is actually extinct and has never been captured on film.

“But!” I say, borrowing Frankie’s excitement and pausing dramatically, “Scientists noticed a lot of similarity between this:”

“and … this:”

“What’s happening here?” I ask.

Frankie (now very helpful): That guy is holding a shark jaw.
Kamiah: Is that a Great White shark?
Mr. Vaudrey: No, that’s a manB from south Florida named Barry… Oh, you meant theB jawB he’s holding.B Yes, the jaw of the Great White is like a smaller version of the Megalodon. Do you see the similarities?

(Go back and forth between the two pictures as students nod).

How do you think those two sharks are related?

Tionne: Well, like what if the Megalodon was… like… theB ancestor… of the Great White?
Luis: No, it’s not.B This one is way smaller.
Tionne: Yeah, it is! Look at dinosaurs and like… lizards and stuff!
Mr. Vaudrey: You’re both right.B The Megalodon is related to the Great White shark, but the Great White is way smaller. Does anybody disagree?

Scientists noticed what Tionne noticed; that the jaws are similar and the Megalodon was probably related to the Great White shark that we have today. Here’s the thing, though: The skeleton of a shark isn’t bone, it’s cartilage. So we don’t actually have a full skeleton of the Megalodon and don’t know how long it is. Scientists noticed this, though:

The teeth are almost identical, except for the size. They also noticed that the bigger the Great White, the bigger the jaw.

[Lead students through discussion about proportional relationships until…]

Dream Student: So if we compare the teeth, we can figure out the length?B ¹
Vaudrey: What luck! We happen to have such a format on page 68! Go there.

Fanda: Wait, how long is the Great White?
Vaudrey: Oh, yeah. Here.

Teacher Notes:

Depending on the class, you can go through unit conversion, take guesses first, whatever. I followed the flow of the class; if they had concerns about the units, we converted feet to inches or mm or whatever. If they didn’t care, then I just made sure the end result was in feet and they could explain how they knew.

The numbers in black on the right side were technically the “answer”, but didn’t quite have the catharsis that we wanted. So we went outside.

Students took 20 paces from the blacktop, which varied “much like the size of a shark would have varied between 56 and 64 feet.

Turn around and look back at the blacktop.”

Vaudrey:B The distance from you to the blacktop is the about length of a Megalodon.
Alan: Holy shit!

It’s a good day when students are involved enough to curse.

Then we went back inside and I showed them this:

and this:

Maria: I wonder how tall the fin is.
Fernando: Could the big shark swallow a bus?
Ramiro: How many humans could it eat at once?
Vaudrey: Let’s get into those questions tomorrow.

All the downloads are here.

And click here to email me and book La Cucina Matematica for your district, school, or county.

~Matt “Big Shark” Vaudrey

^{1. I teach RSP, it’s unlikely that they would jump here so quickly. An actual 2nd period would involve turning to yesterday’s page in the notebook and looking for similarities.b)}