Prove It

Summary
D.W. discovers a passion for science, but her explanations for questions like why the sky is blue don't sound right to Arthur.

Plot
Brain explains the Earth's rotation that causes day and night, when Arthur stops him, saying that they don't understand what he's saying. We then see he's talking to Baby Kate and Pal.

Prove It

After the title card, Arthur and Buster are watching NOVA, when D.W. distracts them, annoying Arthur. Later, Arthur and Francine are playing catch, when Francine spells a word D.W. can't understand. Later, Arthur wants to see the sci-fi movie 5,000 Explosions and a Supernova. D.W. wants to go too, but Arthur won't let her. In Arthur's room, D.W. talks to Brain, annoying Arthur. Brain shows D.W. some science fun while Arthur is doing his homework. At dinner, Arthur blames D.W. for bothering Brain, which D.W. denies. After dinner, D.W. wants to go to the exploratorium, but Arthur won't let her.

The next day, D.W. starts her own world of science and won't let Arthur in, but Arthur loans her 73 cents, a ring, a torn horse sticker, and a sourball. D.W. presents her exhibit wrong, much to Arthur's annoyance.

Finally, Arthur tells his parents he wants to take D.W. to the exploratorium, which his dad is surprised by. "Yes, please!" Arthur replies. "Tell her she has to go!"

With that, Arthur and the Brain take D.W. to the exploratorium to learn the correct scientific answers to her questions. D.W. then states that her theory that Arthur would beg to take her to the exploratorium was correct, much to his shock. Brain comments that D.W. is much smarter than she seems, finishing the episode.

Major

 * D.W. Read
 * The Brain
 * Arthur Read
 * David Read

Minor

 * Francine Frensky
 * Buster Baxter
 * Emily
 * Timmy and Tommy Tibble
 * Kate Read
 * Pal
 * Mrs. Powers

Cameo

 * James MacDonald
 * Kyle
 * 3rd Grade Female Aardvark
 * Liam
 * Amanda Hulser
 * Lucy
 * Lisa
 * Maryann
 * Edwin
 * 3rd Grade Male Cat
 * Mrs. Fink
 * Jane Read

Trivia

 * D.W. pronounces  exploratorium wrong in this episode.
 * Running Gag: Kate sucks onto a ball when she gets it.

Cultural references

 * The "NOVA" television program that Arthur and Buster watch is a real show, not to mention the fact that it is from PBS, the same company that provides Arthur (both shows are produced by WGBH).
 * The Exploritorium museum Arthur, D.W., the Brain and his mom visit is similar to the Franklin Institute, which is in Philadelphia, Pennsylvania.

Errors

 * When The Tibble Twins raise their hands, Tommy has Timmy's blue scarf and Timmy has Tommy's red scarf then in the next shot of the Tibbles they have their regular scarves again.
 * When D.W. gets the second lot of people in line, the Tibble Twins are seen in the line but a couple of seconds later, they are seen coming out of D.W.'s Explainatorium.