Ahead of today's sole free practice session, the air temperature is 23 degrees C, and the track temperature is 29 degrees.

After a strange second session yesterday, when difficult track conditions together with fuel loads and tyre choice made it difficult to tell the true order of things, we're hoping to get a far better idea of what's what in this session, as the teams prepare for the all-important qualifying session. It will be particularly interesting to see if Red Bull maintains its Friday form.

The lights go green, and Rosberg leads the traffic jam at the end of the pitlane, from Trulli, Fisichella, Glock, Kubica, Bourdais and Davidson. In the McLaren garage, Lewis Hamilton climbs into his car.

Webber is out early, running a set of the soft tyres. Like the fifteen other drivers who have gone out before him, he completes an installation lap and then heads back into the pits. Elsewhere, Vettel, who is happy with his car, feels that the track is "dirty" after being left open overnight.

Seven minutes into the session, Heikki Kovalainen is the only man on track. He laps the Albert Park track at an almost leisurely pace. The Ferraris, Hondas and Hamilton have yet to make an appearance.

Ten minutes into the session, Anthony Davidson is the first driver to go out for a second run. Lewis Hamilton and Takuma Sato head down the pitlane behind him. More and more drivers leave their garages, Trulli, Fisichella, Heidfeld and Bourdais amongst them.

Davidson posts the first time of the day, crossing the line at 1:33.744, moments later, Bourdais posts 29.366. Elsewhere, Ron Dennis emerges from the McLaren garage with what appears to be a new pair of headphones.

Barrichello and Massa are on track, as Heidfeld goes second behind Bourdais, who has improved with a 28.401. Elsewhere, Glock is the first driver to enjoy a little detour - we are sure there will be many more.

As Kubica goes quickest (28.256), Raikkonen heads down the pitlane and Fisichella follows Glock's example.

Massa goes fifth with a 28.992 as Raikkonen begins his first flying lap of the day. Meanwhile, Rosberg goes quickest ahead of Vettel, Kubica and Glock.

Glock takes the top spot with a 27.739, as Raikkonen slips in behind, crossing the line at 27.956. As Alonso begins his first flying lap, Massa goes quickest with a 27.707. On board footage shows Alonso really fighting with the Renault. Nonetheless, the Spaniard goes quickest in the second sector, and again in the third, taking top spot with a 27.487.

The double World Champion's joy is short-lived however, as Raikkonen retakes the lead with a 27.444.. Moments later however, Rosberg goes quickest with a 27.196.

As Alonso goes quickest again (27.167), Webber is on a hot lap, running the softer compound. The Australian crosses the line at 28.025 to go seventh, as Hamilton gets out of shape and misses a corner.

Hamilton, on mediums, is pushing hard, but by the second sector he is down on Alonso, who posted his best time on the medium compound. The Englishman crosses the line at 27.509 to go fourth.

Almost half-time, and still no time from Trulli, Piquet, Coulthard or Kovalainen.

Piquet goes seventeenth, crossing the line at 29.635, as Bourdais takes ninth, one spot ahead of his Toro Rosso teammate.

At half-time, it's: Alonso, Rosberg, Raikkonen, Hamilton, Nakajima, Massa, Glock, Webber, Bourdais and Vettel. Meanwhile, Piquet's misery continues, the Brazilian going off and having to take a long trip through the gravel, much to Flavio Briatore's obvious frustration on the pitwall.

"I was a bit off the track," Piquet tells his crew, possibly hoping that the hadn't noticed. "However, there's no damage," he assures them.

Vettel (medium) improves to eighth, as Trulli remains the only driver yet to post a time. Next time around, Vettel improves to fifth, crossing the line at 27.517. Elsewhere, Fisichella goes ninth.

Hamilton (medium) is back on track, however by the second split he's already 0.5s down on Alonso. He's quickest in the final sector, but remains 0.342s shy of the Spaniard.

Bourdais informs his crew that his first lap is fine, but after that it stall starts to fall apart, what with the rear wheels locking, the tyres graining and generally everything being thoroughly rotten. Elsewhere, Raikkonen goes cross-country. Nonetheless, he improves with a 27.163 to take the top spot, ahead of Alonso, Rosberg and Hamilton. The Finn is on the medium compound, which appears to be the compound to have at this stage.