He opened a plastic bag full of ping-pong balls and dumped them into the water.
Next, Mr. Martin took an empty plastic soda bottle and attached a brick to either side of it using duct tape.
“What’s that for, Mr. Martin?” somebody asked.
“You’ll see,” the teacher replied. “When molten rock pours out of a volcano, it’s called lava. It’s really hot, but it moves slowly, so people can usually evacuate in time. Sometimes though, the top of the mountain will just explode and release millions of tons of ash, flying boulders, pulverized rock, and poisonous gases.”
“I think there was one of those volcanoes in the boys’ bathroom yesterday,” Stuart cracked. “Whew! Talk about poisonous gases! We all had to evacuate.”
“WILL YOU SHUT UP FOR ONCE IN YOUR LIFE?” Isabel suddenly shouted. “Do you have to be stupid all the time?”
Her outburst even shocked herself. She was usually quiet in school. Most of the time, she limited her displays of disgust to eye rolling and head shaking. But after everything she had been through on the Titanic and at Gettysburg, Isabel had lost some of her timidity and gained some confidence to say what was on her mind.
Everybody stopped for a moment and looked at her. Even Stuart was shocked. He had no comeback. A few of the girls clapped their hands quietly.
“Anyway,” said Mr. Martin, “when the top of the mountain explodes, the result is called pyroclastic flow. It moves at the speed of a hurricane and can get as hot as eighteen hundred degrees.”
Mr. Martin put the bottle gently on the ground. Then he stuck a funnel in it and began to fill it. Kids began covering their ears.
“What’s that stuff, Mr. Martin?” somebody asked.
“Liquid nitrogen,” the teacher replied. “You can also use ammonium dichromate.”
He quickly capped the soda bottle and lowered it into the garbage can full of water.
“Now stand back, everybody!” he announced. “It should be about ten seconds.”
The class began counting down.
“Ten . . . nine . . . eight . . . seven . . . six . . . five . . . four . . . three . . . two . . . one!”
Nothing happened.
A few more seconds passed. A little smoke started rising out of the garbage can. And then, BOOM!
The soda bottle blew its top, and red water, smoke, and ping-pong balls were launched in the air and rained down all over the courtyard.
“Whoa!” “Cool!” “Awesome!”
“That’s what you call a Plinian eruption,” Mr. Martin announced. “Of course, if this had been a real volcano, it would be no laughing matter. There would be death and destruction for the people who live in the area. There could be earthquakes, landslides, acid rain, or flash floods.”
Mr. Martin had a satisfied grin as he looked at the students’ faces. Even Stuart and his obnoxious pals were locked in now. It’s just about impossible to be bored when you’re watching an explosion. Blowing stuff up is undeniably cool.
“The biggest known volcano in our solar system is on Mars,” Mr. Martin told the class. “It’s three hundred seventy-three miles wide and thirteen miles high.”
Nobody said “whoa” or “cool” or “awesome.”
Mr. Martin went on to tell the students about some other famous volcanoes, but almost immediately, he realized he had pushed his luck. Isabel was still jotting down notes, but most of the class had already lost interest and were chatting about other things.
Mr. Martin sighed, silently lamenting the short attention span of today’s kids. Maybe they got something out of the demonstration, he hoped.
A few minutes after the dismissal bell rang, Isabel was at her locker. She turned on her cell phone to find a group text already in progress. . . .
Julia: What R you guys doing?
Luke: ZIP. U?
David: Want 2 get pizza?
Julia: Where?
Luke: I’M IN. WHERE ISABEL?
David: Meet at Boylston and Tremont in 30
Boylston Street and Tremont Street intersect at the corner of Boston Common, one of the prettiest parks in America. The Boston subway, which is called the T, stops right nearby, so it was a convenient meeting spot for the Flashback Four.
The group hadn’t seen each other since getting back from their Titanic adventure, so a long group hug was in order. Then they grabbed slices at a nearby pizza joint and sat down on a bench on the south side of the park. It reminded them of the bench they’d ended up on when the Carpathia had docked in New York.
“It feels weird, doesn’t it?” David asked after the usual pleasantries had been covered.
“Yeah,” Julia replied. “What is it?”
“I don’t know,” said Isabel. “I’ve just been feeling strange ever since we got back. It’s like I’m a different person or something.”
“Me too,” David said. “Can’t put my finger on it.”
“I can,” Luke said. “I’m bored. We’re all bored. We were on the Titanic. We almost died. Now we’re back home, going to boring school. Doing boring homework. Living boring lives.”
“It was exciting, wasn’t it?” Isabel said a little mischievously. “I still can’t believe we made it back.”
“That will probably be the most exciting thing that ever happens to any of us,” Julia noted. “It’s a little depressing, huh?”
“Remember when that rich guy—John Jacob Astor—gave us his money?” recalled Isabel.
“Remember when he locked us in that stateroom, and then the ship hit the iceberg?” recalled Luke.
“That was cool,” David said. “I mean, it wasn’t cool at the time, but it’s cool to think about now that it’s over.”
“Face it,” Luke told the others. “We’re officially boring now. We’ll never do anything that exciting again. It’s all downhill from here.”
They walked through Boston Common in silence until they reached the famous Frog Pond near the north end of the park. Some kids were tossing a Frisbee back and forth. A couple was taking selfies on the bridge in front of the famous swan boats. That’s when Luke noticed a couple of women across the pond. One of them was sitting in a wheelchair.
“Wait a minute,” he said. “Is that . . .”
“Miss Z!” Isabel shouted.
The foursome ran over find Miss Z with Mrs. Vader sitting near the edge of the pond,
