A grown man is drifting away over the neighborhood in a pair of helium trousers.
That is the plot, and it is a very good joke. What sits underneath the joke is a physics question with a real answer: how high does he go, and what stops him. Ada Twist, who asks questions the way other children breathe, has to work it out fast, with Rosie Revere and Iggy Peck and her own brother Arthur helping.
Second in the Questioneers chapter book series, by Andrea Beaty. Short chapters, heavily illustrated, and a good deal more physics in it than the cover suggests.
The science it actually teaches
This is the most science-carrying of the Questioneers chapter books, and the reason is that its plot is a buoyancy problem you cannot solve by being brave.
Start with why helium goes up at all. Most children are told that helium is light, which is true and useless. The real reason is that a helium balloon weighs less than the air it shoves out of the way, so the air closes in underneath and pushes it up. Floating in air works the same way floating in water does. Once your child has that one sentence, a hot air balloon, a boat, a submarine and a stone dropping into a pond all turn into the same idea.
Then the good question, the one the book puts on its own cover copy: will he float off into space? No. The reason is the part worth having. The air does not stop at a wall. It thins out as you go up, so as the trousers rise, the air pushing underneath them gets weaker. They rise until the air outside is as thin as the gas inside, and then they hang there. Every balloon has a ceiling, and the ceiling is set by the air, not by the balloon.
Then, how do you get him down. There are only two moves, and a seven year old can name both once you point at the problem: make him heavier, or let gas out. Every lifting problem in the world runs on those two levers.
One more, and it is the throwaway question the book opens on. Why does hot coffee smell stronger than cold coffee? Because warmth makes the molecules move faster, so more of them leave the cup and get up your nose. That is a real answer to a real kitchen question, and it is the sort of thing a child repeats at breakfast for a month.
The child it lands with
The one who asks how, not what. The one who wants the mechanism and gets restless during the feelings.
A child who already knows these faces from the picture books and is ready for chapters will take this happily, because only the reading got harder. And a child who has decided they are bad at science will not notice they are doing any. Nothing in here is labelled physics. It is a man stuck in the air and four kids arguing about how to get him down.
One place to stop and talk
Buy a helium balloon before you start the book. One is enough.
Stop reading when Uncle Ned is airborne and hand the balloon over. The job is to bring it down without holding it. Paper clips on the string. A bit of tape. A squeak of gas let out. Then get to the harder version: how many paper clips make it hover instead of sink. That hovering point is the whole idea in the book, and once a child has felt it with their hands, the physics is theirs and it stays.
What to know going in
The peril is real peril. A man your child likes is floating away and might not come back, and the book plays it for laughs without pretending it is nothing. A five or six year old who takes jeopardy to heart may want you sitting next to them. Most will find it hilarious.
Two practical things. This is book two. It stands alone and nobody will be lost, but the friendships were built in book one and they land better in order.
And this one I mean: a child who has just finished a book about trousers that carry a man into the sky will go and find a balloon. Have the conversation about helium and party balloons before you close the cover, not after you hear a chair being dragged across the kitchen.
Where to get it
$7.99 at Ada Twist and the Perilous Pants. If you are buying exactly one Questioneers chapter book and your reason is science rather than character, buy this one, because the buoyancy in it outweighs the mystery plots in the others. If your reason is reading level, or the child is new to chapters, start at book one and come back here once chapters stop being work. It sits on the Stealth Science shelf for one sentence in particular: the one about the air closing in underneath.
If your child liked this one
Books we have written about that sit close to this one, by reading level and by subject.
Iggy Peck and the Mysterious Mansion: Reading a House
Iggy Peck and the Mysterious Mansion: The Questioneers Chapter Book #3 by Andrea Beaty
Grade 1 to 4
Rosie Revere and the Raucous Riveters: Not a Picture Book
Rosie Revere and the Raucous Riveters: The Questioneers Chapter Book #1 by Andrea Beaty
Grade 1 to 4
Caterflies and Ice: The Book Where Zoey Gets It Wrong
Caterflies and Ice: Zoey and Sassafras #4 by Asia Citro
Grade 1 to 4
Dragons and Marshmallows: The Science and the Catch
Dragons and Marshmallows: Zoey and Sassafras #1 by Asia Citro
Grade 1 to 4
Browse every book we have written about by age, by kind of book and by subject: Find the right book for your child. Or see the whole Stealth Science shelf.
