What's Inside a Volcano?

Teo had been waiting for this day for three weeks, two days, and — she checked the clock on the classroom wall — about four hours.

Today was Share Something You Know day in Ms. Huang's class, and Teo was ready.

She had her poster. She had her diagram. She had her mom's old safety goggles pushed up on top of her head like a headband. And she had facts. So many facts.

The other kids had already gone. Marcus shared about how hermit crabs switch shells. Priya explained why the moon looks different every night. Jordan brought in his grandma's recipe for cornbread and gave everyone a piece, which Teo thought was maybe not exactly "something you know" but was delicious, so nobody minded.

Now it was Teo's turn.

"Okay, Teo," said Ms. Huang, smiling. "You're up."

Teo walked to the front of the room, unrolled her poster, and taped it to the whiteboard. It was a giant drawing of a volcano, cut right down the middle so you could see inside. She'd colored it herself. The outside was brown and green with tiny trees. The inside was red and orange and bright, screaming yellow.

She pulled the safety goggles down over her eyes.

"Today," she said, in her most important voice, "I'm going to tell you what's inside a volcano."

"Is it lava?" said Diego, from the second row.

Teo pointed at him. "Not yet. We're not there yet. You have to go in order."

Diego sat back.

Teo slapped the top of the poster. "Okay. So the first thing you need to know is that the Earth is like a hard-boiled egg."

Priya wrinkled her nose. "It is?"

"It IS," said Teo. "My mom told me, and she goes inside volcanoes, so." She let that hang in the air for a moment. "The outside of the Earth is the shell. It's called the crust. It's hard, and it's thin, and we live on it."

She knocked on the floor with her shoe. "That's the crust right there."

"Under the floor?" asked Amara.

"Under EVERYTHING. The crust goes under the school, under the parking lot, under the ocean, under your house, under everywhere. It's like the whole planet is wrapped in a crunchy blanket."

A few kids giggled. Teo pulled the goggles up, then pushed them back down. She was on a roll.

"Under the crust, there's the next layer. It's called the mantle." She pointed to the orange part of her diagram. "The mantle is super thick and super hot, and it's made of rock — but the rock is so hot that it moves. Really, really slowly. Like..." She thought about this. "Like if you left a cheese sandwich on the dashboard of a car on the hottest day ever and the cheese got all gooey and started sliding everywhere."

"Ewww," said Jordan.

"It's NOT eww," Teo said firmly. "It's geology."

Ms. Huang covered her mouth with her hand, but Teo could see she was smiling behind it.

"Okay, so THIS is where it gets good." Teo pointed to a crack in her diagram, where red and orange snaked upward through the brown layers. "Sometimes, deep deep down, the rock gets SO hot that it melts all the way. And melted rock underground is called magma."

She said magma the way you'd say magic, low and slow.

"Magma pushes up. It squeeeezes through cracks in the Earth. It finds little tunnels and weak spots. It's like — okay, you know when you squeeze a juice box and the juice shoots out the little straw hole?"

Every kid in the room nodded. They knew juice boxes.

"The Earth is the juice box," said Teo. "The magma is the juice. And the volcano?" She smacked the top of her poster. "The volcano is the straw hole."

"WHOA," said Diego.

Teo grinned. She couldn't help it.

"So the magma pushes UP and UP and UP through the inside of the volcano — that part's called the vent — and when it finally comes out the top..." She looked around the room. "THAT'S when it's called lava."

"Wait," said Marcus. "Magma and lava are the same thing?"

"Same stuff, different name!" said Teo, bouncing on her toes. "Underground, it's magma. When it comes outside, it's lava. Like how water is water, but when it freezes you call it ice."

Marcus looked impressed. Teo felt like she could float.

"And it's not just lava that comes out," she continued. "There's also ash — tiny tiny bits of rock that shoot into the sky like the world's worst confetti. And gas. Lots of stinky gas. My mom says some volcanoes smell like rotten eggs."

"Your mom has SMELLED a volcano?" Amara's eyes were huge.

"She has smelled LOTS of volcanoes," said Teo proudly. "She wears a special mask. And special boots. And she takes the temperature of the lava with a really long thermometer so she doesn't have to get too close." She paused. "But she does get pretty close."

The room was quiet. Everyone was looking at Teo. Not bored-quiet. Amazed-quiet.

"Here's the other cool thing," Teo said, pointing to her diagram where she'd drawn green plants and brown dirt around the base of the volcano. "After a volcano erupts and the lava cools down, it turns back into rock. And over a long, long time, that rock breaks down and becomes soil. And that soil is like the BEST soil. Things grow like crazy in it. My mom showed me pictures of volcanoes in Hawaii where there's flowers growing right out of old lava fields."

She stepped back from her poster and pulled the goggles up onto her forehead.

"So basically," she said, "a volcano is the Earth letting out what's been building up inside. And after all that big, scary explosion... stuff grows."

For a second, nobody said anything.

Then Diego raised his hand. "Can your mom come to our class?"

"I already asked her," said Teo. "She said yes. She's coming in March. She's bringing real volcanic rock."

The class erupted — and not the quiet kind. The loud kind, with cheering and desk-tapping and Jordan yelling, "WILL SHE BRING CORNBREAD?"

Teo laughed. "I'll ask."

Ms. Huang started clapping, and the rest of the class joined in, and Teo stood there at the front of the room with her poster and her goggles and her red and orange and screaming yellow diagram, and she thought that this — this right here — was better than any volcano.

Well. Almost.

On the way back to her seat, Priya leaned over and whispered, "How do you know all that stuff?"

Teo shrugged, but she was smiling so hard her cheeks hurt. "I just really like volcanoes."

And that was true. She really, really did. She liked the way her mom's eyes lit up when she talked about fieldwork. She liked the big words that felt important in her mouth — magma, mantle, eruption. She liked that something so wild and fiery could make things grow.

That night, Teo sat at the kitchen table drawing a new poster. This one was about earthquakes.

Her mom looked over her shoulder and said, "What's this for?"

"Next Share Something You Know day," said Teo. "I want to be ready."

Her mom kissed the top of her head. "You always are."