Just an Old Fashioned Lab Song... is the second part of the 32nd episode of season 2 in Dexter's Laboratory. It originally aired on March 25, 1998. In this episode, Dexter has to take piano lessons from Professor Williams, but his hidden talent for music is exposed when the Professor stumbles into his lab.
Singer-songwriter Paul Williams guest stars in this episode as Professor Williams.
Concerned about Dexter's tendency to remain inside all day, Mom and Dad force him to take piano lessons, much to Dexter's chagrin. Mom and Dad had previously provided piano lessons for Dee Dee, who is banging chaotically on the piano as they speak. As part of his first lesson, Professor Williams tries to teach Dexter the art of the arpeggio. Williams is unfazed by Dexter's reluctance to play, and tells Dexter to practice arpeggios until their next lesson. Seasons pass, and Dexter does not improve at all, nor does he make any attempt at doing so.
Come the time of their next lesson, Dexter is busy working in his laboratory. Professor Williams enters Dexter's room in search for him; he unwittingly comes across a scanning device that grants access to the laboratory. Due to his diminutive stature, identical to Dexter's height, he is mistaken for Dexter and granted entry into his lab. Once inside, Williams is amazed by Dexter's massive laboratory; though Dexter immediately tries to show him out, Williams points out to him that one of his machines is producing a sound similar to an arpeggio.
In a flash of inspiration, Williams performs a song about how well music goes together with science; though initially reluctant, Dexter joins in Williams' performance, using a piece of laboratory equipment to play a musical solo. Their session ends with the pair laughing, and Williams takes his leave. Dexter is immensely overjoyed to see him leave, and his old attitudes about music seem to resurface, if indeed they were ever gone at all. The episode ends with Dexter smashing the "arpeggio machine" with a wrench to make it stop making music.
At one point, Professor Williams utters the phrase, "we've only just begun"; this is a reference to Williams' hit for The Carpenters of the same name. The line is followed directly by a short snippet of the song's melody.
Before Professor Williams begins his song, he utters the phrase "Here comes inspiration!," a reference to Williams' 1974 album of the same name.
When Dexter pleads to his parents to not have music lessons, Mom and Dad state that Dee Dee has apprently taken piano lessons (although she really cannot play).
Although Dexter is reluctant in the fields of music in this episode, he has expertise in both science and music in the episode Dee Dee Be Deep
Ironically, Paul Williams cannot really play the piano.