During each episode of the show, numerous experiments are carried out to verify whether common conceptions are true (such as whether it is possible to run across a pool of custard) or simply to create impressive explosions.

The second series also introduced Charlotte Hudson as a third, but minor, host, and saw the introduction of what then became long term character "Professor Myang-Li", played by Rachel Grant.

Dr. John P. Kilcoyne, Associate Dean of the University of Sunderland had a regular slot where he mixed various chemicals to see whether they "fizz" or "bang".

In addition, Vic Reeves appeared as the Russian scientist Uri Abusikov, along with his assistant Ursula, attempting to destroy things with liquid nitrogen.

Hammond's growing commitments to Top Gear and his contract with the BBC meant that he was finding it increasingly difficult to fulfil his role as presenter of Brainiac.

[2] Reeves was brought in as replacement host shortly after the end of the fourth series and before Richard Hammond's near fatal crash.

Other new segments included "Gas Bang Wallop" featuring a character called Barry Bernard who destroys things with gas, "Chemistry Deathmatch" in which regular characters Dr Bunhead and Professor John Kilcoyne go head-to-head to produce the best experiments, "Custard Dreams" which follows the adventures of a Brainiac who discovers he can walk on custard, and "Stars in Their Caravans" which sees a variety of UK celebrities trapped in caravans, in a mock game show which results in large explosions.

It showed the violent reactions of metallic sodium and potassium with water, in which the hydrogen produced subsequent explosions, and intended to demonstrate the even greater reactivity of rubidium and caesium by dropping them into a water-filled bathtub.

A wire connected to an offscreen detonator can be observed on the side of the bathtub filled with water for a brief moment during the caesium experiment.

Caesium, on the other hand, does create an explosion and destroys the apparatus by shattering the glass and blowing a hole in the side of the container.

One of the show's recurring skits featured heavy metal band Twisted Sister's song "You Can't Stop Rock 'n' Roll" in which a stereo playing the song is destroyed in various ways to humorously demonstrate that you can in fact "stop rock 'n' roll" using the shown methods.