Two Masterclasses were filmed for each episode, with the subject based on a technical aspect a team was focused on that day.
Although never explicitly stated, the teams were aware of the task 3 weeks before filming occurred. However, the everyday items and furniture in their respective rooms and workshops was kept secret until filming. The Scientific Principle (Day 2) & Mystery Object (Day 3) were also true secrets, only revealed to teams on camera at the start of their 10 hour build day.
"Rube Goldberg Machines" is the more common name for these types of contraptions, versus being called "Chain Reaction Machines," "Heath Robinson Machines" or "Crazy Contraptions." Due to legalities with name licensing, the phrase "Chain Reaction Machine" was chosen as it holds no copyright issues and best describes the nature of these devices.
An unaired Masterclass featured the globe seen on the main stage. Hidden inside was a 16 step chain reaction machine designed to serve Richard and Zach tea & biscuits for their final Masterclass. This machine can be seen on Zach's Youtube Channel.
Zach's Guinness World Records are for having built the largest Rube Goldberg Machines in history. In 2011, a machine designed to water a plant ran perfectly twice in a row with 244 steps. In 2012, this record was shattered by a machine with 300 steps to blow up and pop a balloon. By comparison, the longest machine in season 1 has 65 steps.