Beakman (Paul Zaloom)
- Anime Hair
- I Am Not Spock: Compare Beakman, the child-friendly scientist, to his actor, Paul Zaloom, the VERY adult political puppeteer.
- Mad Scientist
- Student and Master Team
Lester the Rat (Mark Ritts)
- Becoming the Mask: In early episodes, he resented having to wear the rat costume as he was a professional actor whose agent booked him a crummy role on a kids' edutainment show. As Flanderization kicked in, he apparently began to actually identify himself as a man in a rat suit as if it were his species(as well as the fact that friends and family members inexplicably became people in rat suits as well).
- Big Eater
- Classically Trained Extra: Started out this way when the show began.Lester: "To be, or not to be?" That is the question, not "what is snot?"!
- Deadpan Snarker: He would be one if he wasn't constantly proven wrong.
- Extreme Omnivore: Right along with Big Eater.
- Flanderization: As the series progressed, the disgruntled-actor-in-a-rat-suit bit was dropped in favor of Lester's more disgusting traits.
- The Lab Rat: Subverted, despite being the guy in the lab in the rat suit.
- Audience Surrogate / The Watson: Beakman's assistants help think through the answer, ask the obvious questions, and generally keep Beakman moving toward a response to the readers' questions.
- Genki Girl: All three were highly energetic, particularly when rushing in from off-screen or during the intro to Beakmania.
Josie (Alanna Ubach)
- Awesome Moment of Crowning: The last segment of Josie's last episode shows kids how they can do their own research (using the question "How do fireworks make those neat colors?" as an example). Beakman points her to resources, but Josie does most of the legwork and provides the final answer herself.
- Precocious Crush: Josie is often awe-struck by Beakman's knowledge.
Liza (Eliza Schneider)
- Fingerless Gloves
- Hospital Hottie / Meganekko: The "Dr. Liza" segments.
- Replacement Scrappy: Liza gets some hatred from fans for not being Josie, but she gets it fairly easy compared to Phoebe.
Phoebe (Senta Moses)
- The Cast Showoff: Senta's martial arts training was put to good use in a segment about breaking boards.
- Quirky Curls
- Rapid Fire Interrupting: At least a couple of times per episode, which only added to her "bratty know-it-all" status.Beakman (after two of these interruptions back to back): Okay, Phoebe: Since you know everything...
- Replacement Scrappy: She's hated by fans even more so than Liza, due to the fact that she's not Josie or Liza.
- School Nurse: Nurse Phoebe. Most definitely the Western version.
Don and Herb (voiced by Alan Barzman and Bert Berdis)
- Book Ends: Each episode begins and ends with a scene of them.
- Everything's Better with Penguins
- Greek Chorus
- Reaction Shot: Often get one when a piece of information given in the show relates to them somehow.