In Ms. Frizzle’s class, we had been learning about animals’ homes for almost a month. We were pretty tired of it.
So everyone was happy when Ms. Frizzle announced, “Today we start something new.”

"We are going to study about our earth!" 発言しました Ms. Frizzle. She put us to work 書く reports about earth science.
“And for homework,” she said, “each person must find a rock and bring it to school."

But the 次 day, almost everyone had some excuse.

Only four people had done their homework. And Phil was the only one who had found a real rock.

“I guess we’ll have to go on a field trip and collect rocks,” 発言しました Ms. Frizzle.

あなた never know what will happen on a trip with Ms. Frizzle.
Her new dress was trip in itself.
At first the old school bus wouldn’t start.
But finally we were on our way.

When we came to the field, all the kids wanted to get out of the bus.
But suddenly, the bus began to spin like a top.
That sort of thing doesn’t happen on most class trips.

When the spinning finally stopped, some things had changed.
We all had on new clothes.
The bus had turned into a steam shovel.
And there were shovels and picks for every kid in class.
“Start digging!” yelled Ms. Frizzle.
And we began making a huge hole right in the middle of the field.

Before long—CLUNK!—we hit rock.
The Friz handed out jackhammers.
We began to break through the hard rock.

“Hey, these rocks have stripes,” 発言しました a kid.
Ms. Frizzle explained that each stripe was a different kind of rock.

We chipped off pieces of the rocks for our class rock collection.
“These rocks are called sedimentary rocks, class,” 発言しました Ms. Frizzle. “There are often fossils in sedimentary rocks.”

Wouldn’t あなた know it? Just when we were finding lots of fossils, Ms. Frizzle said, “Back on the bus, kids.”
Then, as we were driving along, we heard rock crumbling underneath us.
Down we went.
Everything was pitch black.
And we were falling, falling, falling!

We landed with a bump.
Ms. Frizzle switched on the headlights.
We had fallen though a hole into a huge limestone cave.
“Rain water has been dripping down through the earth for ages,” 発言しました Ms. Frizzle. “The water wore away this cave in the rock.”

We wanted to stay for a while, but suddenly, the bus sprouted a drill. It started boring through the rock.
Frizzie shouted, “Follow that bus!”
And down we went.

The farther down we went, the hotter it got.
The rocks were harder, too.
“These are rocks that were changed from one kind to another kind によって heat and pressure,” explained the Friz. “Rocks that were changed are called metamorphic rocks.”

We went down even farther toward the center of the earth.
We hit rock that was formed billions of years 前 from a pool of melted rock under the earth’s surface.
Rock like this is called igneous rock.

We had dug all the way through the earth’s crust.
It was so hot now that Ms. Frizzle told us to get back in the bus.

She stepped on the gas, and the bus started really drilling.
Soon we were actually inside the earth. It was hot, hot, hot!
And it got hotter and hotter as we zoomed toward the center.
We were glad when Ms Frizzle headed out again.
We reached the earth’s crust and drove straight up through a tunnel of black rock.
It was great to see the sky.

Then we looked around.
We had come out on an island in the middle of the ocean!
“Isn’t this wonderful, class?” 発言しました Frizzie. “We’ve driven right up on a volcanic island!”
It didn’t look like much. But if Ms. Frizzle was right, the whole island was one big volcano!

We were nervous, but Ms. Frizzle made us collect some rocks.
She 発言しました they had all hardened from melted rock that had come out of the volcano.
Then, suddenly, we heard rumblings from below.

We scrambled into the bus.
The Friz turned the ignition key and stepped on the gas.
Nothing happened. The bus would not start!
We thought we were goners!

Red-hot lava came streaming out of the volcano.
Some of it shot into the air like a fountain.
Some of it flowed over the land like a river.
Our bus went along with it—right into the sea.

When the red-hot lava hit the water, it made a huge 雲, クラウド of steam.
All we could see was white.
We seemed to be rising with the steam and floating along.
No one knows how long we floated in the cloud…

but when it finally cleared, we were back in the school parking lot.

It had been a weird trip, but we did get a great rock collection for our classroom.