It's the International Show-and-Tell Competition and Arnold and DA are representing Ms. Frizzle's class. Arnold brings a webbed hoop, left behind by his great-aunt Arizona Joan, the famous archaeologist, but he has no idea what it is! Using clues from the hoop and Joan's journal, the kids make educated guesses about its uses. To test their hypotheses, Ms. Frizzle turns the bus into a "Supposatron," a magical device designed to evaluate guesses. Can the kids solve the puzzle before Arnold and DA take the stage?

What do you do when a 50-foot praying mantis menaces your town? Run like the wind... unless you're in Ms. Frizzle's class and she's taken you on a field trip inside a 1950s sci-fi film. The movie's main character, the power-mad General Araneus (Ed Asner) is determined to destroy the mantis, but Phoebe wants to trap it and save it! Shrinking to the size of real spiders, the kids discover how spiders construct a variety of silky snares, making them world-champion trappers. Can the kids save the mantis and stop Araneus before it's too late?

When Wanda discovers that one of Ms. Frizzle's ancestors was Redbeard the Pirate, she naturally wants to follow the treasure map he left. The map leads the class to a coral reef, where they learn first hand that life there is risky. To survive, they find, many plants and animals form surprising partnerships. But Wanda's not interested in partnerships - she just wants to find that treasure! When Ms. Frizzle turns the class into different sea creatures, Wanda as "Wanda-Anemone," "Wanda-Shrimp," and "Wanda-Remora," begins to understand that partnerships are more valuable then she thought.

In the TV show "TAKING FLIGHT," the remote control of Tim's model airplane is accidentally broken. Wanda and the class find themselves inside the plane learning what it's really like to fly it. In a series of high adventures up in the air, they discover how wings and moving air affect lift and flight, and make it back in time to compete in the Walkerville Model Airplane Rally.

Were dinosaurs the biggest, meanest animals that ever lived? To find out, the kids travel back to the Late Cretaceous Period - 67 million years ago. There, they see dinosaurs eat, hunt, rest, and fight. Some even take care of baby dinosaurs! The kids discover that not all dinosaurs were huge - some were as small as rabbits. And most dinosaurs weren't killers - they preferred plants to dino-burgers. But one meat eater - Tyrannosaurus rex - has a taste for a Magic School Bus sandwich! What happens when Ms. Frizzle enlarges Arnold to T-rex size? Does the Cretaceous creature drop his dinner plans?

Two inches tall, and trapped in a bathroom at Wanda's house, the kids have to get out before Wanda's mother (Rosalind Chao) discovers them. Gathering building materials such as spiky hair curlers, sticky Band-Aids, dental floss, and Q-tips, the kids use what they've learned about structures to construct a series of towers and bridges across the bathroom to an open window! They get across the toilet OK but will they get past the alligator in the bathtub?

In the TV show "UPS AND DOWNS," a monster is sighted in Walkerville Lake! Wanda wants to be first to go under water to find it, but the bus refuses to sink! Meanwhile, Gerri Poveri, a journalist, who needs this monster to boost her sinking ratings, doesn't want Wanda anywhere near the lake. The kids discover there's more than one way to make a bus sink, and in the process discover the real monster of Walkerville Lake.

In the TV show "WET ALL OVER," Arnold and Wanda are due to give a report on the town waterworks. But Ms. Frizzle thinks it's field DRIP time! She turns the bus and class into water drops and the kids evaporate, condense, become rain and rush by river into the ocean. After several trips through the water cycle, they're ready to turn back into regular kids. But the magic key that will get them out of the cycle is locked in the school bathroom! Trying to work their watery way into the bathroom, the kids go through the town waterworks and see how water is purified. Can they get to school through bathroom pipes? Or are they stuck in the water cycle forever?

At this year's Teacherathalon, Ms. Frizzle squares off with Mr. Sinew (Dan Marino), a muscle-bound gym teacher. Sinew easily wins the first of the three events. Thinking there's a problem, the kids go inside Ms. Frizzle to check her out. The bus takes them through her lungs to the bloodstream, where they get pumped through her heart to her calf muscle. But when Frizzle's leg muscle collapses from the strain of winning the second event, the kids discover that her red blood cells can't get oxygen to her muscles fast enough! Can the kids help Frizzle recover in time to win the final race?

When two unlike poles interact, a force draws the magnets toward each other. When two like poles interact, a force repels the magnets.

In a magnetic domain, all of the north poles are aligned in one direction and all of the south poles are aligned in the opposite direction.

The magnetic forces surrounding a magnet are referred to as magnetic fields. The lines of force extend from one pole of the magnet to the other pole. Forces are strongest at the poles.

The magnetosphere is the region around Earth where its magnetic fields are located.

Earth is surrounded by an immense magnetic field, which is strongest at the poles. Earth's magnetic field extends outward, through the atmosphere and into space.

Magnets are surrounded by an invisible force, called a magnetic field, which exerts a force on magnetic materials near it.