Though there is no official lunch-break, the teams were given the opportunity to take a break courtesy of a heavy storm that hit the Sakhir track late morning.
An hour into the session there was a brief downfall which caused the teams to retreat to their garages, and while this soon ended, the subsequent downpour was far more intense.
Until that time, though Romain Grosjean topped the timesheets, the undisputed centre of attention was Mick Schumacher, as he made his F1 debut, with Ferrari.
Completing 33 laps before the rain hit, the German, whose father won five of his titles with the Italian team, had completed 33 laps, with a best time 1.5s off the pace.
Also attracting media attention is Fernando Alonso, who is on tyre testing duty for Pirelli, at the wheel of a second McLaren, the other, carrying out test duties for the team, is driven by Carlos Sainz.
Like McLaren, Toro Rosso is providing two cars for the test, Alexander Albon working on behalf of the Faenza outfit and Daniil Kvyat testing tyres for Pirelli.
Even before the rain arrived track conditions were far from ideal, the circuit having been hit by a sandstorm yesterday.
Check out our Tuesday gallery from Bahrain, here.