Star Jumper: Journal of a Cardboard Genius
Gravity Buster: Journal #2 of a Cardboard Genius
Time Twister: Journal #3 of a Cardboard Genius
all by Frank Asch
all from Kids Can Press
(2006, 2007, and 2008 respectively)
all copies compliments of the publisher
Alex is a genius inventor whose journals will someday be worth billions, or so he says. His inventions are all made of cardboard and silver duct tape and stuff he collects "from the street on garbage day" and keeps in plastic bins under his bed. Best of all, most of his designs require only the amount of energy in two AA batteries.
The most amazing thing about this series is that you completely believe in Alex and his inventions. How could you not? He throws around science facts about string theory, creates complicated equations, draws detailed diagrams of amazing inventions like a space ship, a duplicating machine, an oxygen generator, and an Atom Slider (so his cardboard spaceship can pass through the spaces between atoms).
It's almost as much fun to believe in two kids from Frogcreek, PA who have a Magic Tree House as it is to believe in Alex and his inventions. It's MORE fun to believe in Alex and his inventions than it is to believe in Harry Potter -- what's the big deal about a character who can learn spells and swing around a wand? That's pure magic. All fantasy. Alex is a character from our world who has a pesky little brother, a little bit of a crush on Zoe Breen, and, oh, yeah, the most incredible scientific mind in the history of the human race.
In the three books of the series so far, Alex has created Star Jumper, a spaceship; a new, improved version of the Star Jumper which includes a Gravity Buster anti-gravity device so it won't get sucked into black holes; and a Time Twister to take care of the space-time warp that Einstein explained in his Theory of Relativity.
What's next for Alex? Well, when we leave him at the end of book three, Jonathan and the castle he made have been Micro-Blasted and are sealed in a mayonnaise jar that has holes punched in the lid (and it appears that Jonathan was not making up an imaginary playmate named Merlin!). Alex has defeated the Time Cops of the future by using a time paradox to his own benefit, and Alex and Zoe (and Jonathan in his jar) have been in outer space for 9 days looking for a suitable planet on which to land the Star Jumper.
These books would be perfect for 3rd-6th graders who are doodlers and inventors and superhuman geniuses in the disguise of a normal kid. There are about 144 pages in each book, with words like "prototype" and "parallel universe" and "genius of my caliber," and small but important illustrations every few pages.