Welcome back to our live coverage of the Canadian Grand Prix weekend. Next up is second practice and the big question is whether it will remain dry. There's been rain over the circuit since FP1 but there are reports of it brightening up.

Hamilton was fastest in FP1 in which we saw a few drops of rain but not enough to warrant a switch to wets. But it was tight at the top with the the fastest 11 drivers split by less than a second.

Good news from the McLaren and Caterham camps as both Button and Kovalainen will return to the track.

Button's car had an oil leak that was causing the clutch to slip. That's now fixed according to technical director Paddy Lowe.

And Caterham has Tweeted the following: "Been watching the boys fixing Heikki's car. It's just been fired up and should be ready for him to have a few laps in FP2. Incredible job."

Button completed just 12 laps in FP1 and after all the problems he's been having in qualifying at recent races he'll be keen to get more mileage on the tyres this afternoon. Although Button's problems in recent weeks are still a bit of a mystery as he has often been positive after Friday practice but then failed to deliver on Saturday.

You may have heard that one of the HRT mechanics was hit by de la Rosa's car at the end of FP2. Here's an update from the team: "Good news! Chess, Pedro's 1st mechanic, is still in hospital for further checkups but it seems that he hasn't got any broken bones"

Due to the threat of rain this afternoon, quite a few teams opted to run on super-soft tyres in the morning session to try to gather data. Of the front runners Lotus, Mercedes and Red Bull all tried the softer compound which means they will have a used set for this session whereas McLaren and Ferrari should have new sets.

The other news since FP1 is that Vettel has been given a reprimand from the stewards for clipping Senna as he passed him into the final chicane.

If you have any questions or want to make any comments during the session please get in touch by clicking on the link at the top of this window.

Rain or no rain, this track is always slippery on a Friday and offers a good opportunity to see the drivers working hard behind the wheel. Here's a picture of Alonso catching the rear of his Ferrari on the exit of the final corner this morning.

© Sutton Images

Now there are some suggestions that Button won't be out on track at the start of this session. We'll keep you updated on his movements over the next 90 minutes.

Martin Whitmarsh tells Sky that on fire up there was another problem with the gearbox ahead of the session. But it won't result in a penalty as drivers are allowed to use old gearboxes on Fridays.

So, more bad news for Button at this stage of the weekend, but images from the circuit show him looking fairly relaxed with his girlfriend Jessica Michibata in the McLaren hospitality. It's not all bad...

The session is underway. No cars on the track ... yet.

Vergne breaks the silence in the Toro Rosso and is quickly followed out by Kobayashi. The teams will be keen to get as much running as they can early in this session if rain is on the way.

The weather radar shows that there are lots of patches of rain in the area, but it's hard to say if they will arrive in this session or how heavy they will be if they do.

Incredible! It looks like the sun has come out and the track is flooding with cars as a result.

17 cars on track at the moment, Kobayashi is fastest with a 1:17.709 but the times will tumble with every lap at the start of this session.

Grosjean out-brakes himself into the final chicane. He's not the first man to that this year and won't be the last.

Raikkonen goes fastest qith a 1:17.391 on the super-soft tyres. They will be the same set he used in FP1.

Glock spins at turn one and causes a bit of a road block as he ends up parking across the apex. Grosjean manages to take avoiding action, but misses him by less than a metre.

Rosberg and Hamilton are immediately up to speed and trading fast laps at the top of the timesheets.

Maldonado and Alonso are also in on the act with quick times, not to mention Perez!

Ferrari is running a new exhaust outlet this weekend that doesn't look a million miles away from McLarens. Upgrades are now coming thick and fast on the F2012 and appear to be working.

Perez is not happy with one of the Force Indias after a close call on the circuit.

Perez is not happy with one of the Force Indias after a close call on the circuit.

Meanwhile, Schumacher is getting closer and closer to the wall of champions on the exit of the final chicane. He's got history with that bit of concrete.

Hamilton is now fastest with a 1:15.895 ahead of Schumacher on a 1:16.223.

Senna runs wide at turn eight and cuts the corner for nine. Not the first time he's done that this weekend.

Alonso completes a full 360 degree spin on entry to turn eight. He just clipped the grass on the entrance and that sent him round. No obvious damage to the Ferrari.

Webber runs wide at turn one and takes the tarmac exit road that deposits him on the exit of turn two.

Alonso is the latest driver to skip the final chicane as he continues to explore the limits in the Ferrari.

Di Resta has set the third fastest time. He's hoping for a more competitive weekend after struggling to get a decent weekend together this year. Sixth in Bahrain was his best result.

Webber is up to second now but still 0.468s off Hamilton.

Kovalainen is getting ready to head out now that his car has been pieced back together.

Tommy K asks: "What are the drivers currently running on tires wise?"

Soft tyres for most drivers. Super-softs for Perez, Kobayashi, Vergne, Petrov, de la Rosa, Vettel, Glock, Hulkenberg and Pic.

Sauber on their choice of tyres: "We are giving the super soft tyres a try now. A bit earlier than normal because rain is expected."

Kovalainen is told the rain will come in at about 15:00. So in about 35 minutes. Kovalainen still hasn't been out on the track.

Phil Smith asks if Button's gearbox change "will that be penalised?"

No, the drivers are allowed to use different gearboxes in Friday practice so he will not incur a penalty.

So, Hamilton is still fastest, Kobayashi is second and Schumacher is third. All three are currently in the pits.

Di Resta locks a brake into turn one and ends up sideways in the run-off area. The car is fine and he carries on to set the sixth fastest time on the next lap.

Kovalainen is back on track in the Caterham for the first time since his accident this morning.

Hamilton is out on the super-soft tyres for the first time this weekend.

McLaren clarifies that it changed a seal on Button's gearbox, so it's not the actual gearbox that was changed.

Senna misses the final chicane again. He's now out on soft tyres.

Hamilton is still a fastest with his 1:15.259, Vettel is 0.272s slower, Kobayashi 0.392s slower, Schumacher 0.438s slower and Rosberg 0.619s slower.

Hamilton is told that he's roughly 0.1s faster than his rivals in every sector over the radio.

Lots of mixed messages coming about the chance of rain in the next 45 minutes. At the moment it's still dry and the cars continue to rack up the laps.

Siddesh asks: "Last year's Q3 time to beat was 1:13.381. We are now in P2 and still more than 2 seconds off that pace. Has the track been changed since then? Or are drivers simply hiding their true pace?"

The track hasn't been changed but it does evolve as the weekend progresses and more rubber is laid down by the tyres. It's true that most drivers will be holding something back but the conditions aren't that great at the moment with cloud cover and lower track temperatures.

Senna has hit the wall of champions hard. He's fine and out of the car but the Williams looks in a very bad way and the session has been stopped.

Senna lost the rear on the first apex and then the car snapped back on him in the second part of the chicane. He went backwards into the barrier but the car span round and clouted the barrier head-on too. Both front and rear wings are broken. There's also damage to the suspension on the right hand side. The rear right corner took the brunt of the shunt.

While we wait for the session to restart we've finally tracked down the gearbox regualtions that state: "For the purposes of this Article only, an Event will be deemed to comprise P3, the qualifying practice session and the race." That means any gearbox change on Friday is not penalised so if McLaren have or do change Button's 'box he won't be penalised.

Talking of Button, he is now in his overalls and in the garage so might take part in this session.

Christian asks: "Are the Ferrari's rear wings yellow because they're testing the new exhaust system?"

No, the wing looks yellow because it's covered in aero paint. The teams spray their cars in high-vis paint so they can see how the air is moving over the car's surfaces.

Minos asks: "Have HRT brought new parts for the Canadian grand prix? They were off the pace by a second now they are beating the Marussias and the Caterhams."

HRT has a special low-drag rear wing this weekend, which could explain why they appear to be quicker. It's also worth noting that de la Rosa is fastest through the speed trap.

The session is back underway and Hulkenberg is the first man back on track. Cement dust has gone down at the final corner to soak up spilt fluids from Senna's car.

But judging by the skies overhead there could be a few more fluids spilt on the circuit pretty soon...

Just under 30 minutes remain in this session, Hamilton still fastest by 0.272s from Vettel.

Wayne asks: "Any news on Button, will we see him this session?"

Hopefully quite soon. He's in his overalls and in the garage now. But the big question is will he get out before the rain?

Alonso is looking quick on a set of super-softs but has come up behind an HRT in the hairpin. He goes third fastest as he crosses the line, 0.329s off Hamilton.

Petrov skips the final chicane. It's such a fine line between getting it wrong there and aborting the corner. We've seen lots of drivers abort but Senna got it wrong!

Button is now in his McLaren and looks ready to head out.

Button leaves the garage on soft tyres. The good news is that the track is still dry.

Massa is now second fastest, 0.167s off Hamilton's best.

As I type, Alonso crosses the line to go faster than his team-mate and get within 0.054s of Hamilton's time.

Alonso was saying yesterday that Ferrari needs to work on its one-lap pace and it looks as though they will be fairly competitive this weekend. But it's still early in the weekend and I doubt we've seen the representative times from the likes of Mercedes and Lotus at this stage.

Button goes 19th fastest on his latest lap, 1.989s off Hamilton. He's on the soft tyres and is likely to be working on race pace rather than ultimate pace.

Hamilton is not only fastest in this session but he's also racked up the most laps with 35. A big contrast with team-mate Button who's complaining of a lack of front grip.

At the moment Alonso has the fastest first sector time, Hamilton is fastest in sector two and di Resta is fastest in sector three (which is all about straight-line speed).

Eight minutes left in this session and we might just avoid the rain. Most drivers are well into long runs so plenty of data is being gathered for Saturday and Sunday.

Hamilton, Rosberg and Vettel are all trading similar sector times but we don't know what the fuel loads are. Nevertheless, it looks close from the outside.

Button is now on the super-soft tyre as he tries to fit as much running into the end of this session as possible.

Button clocks the 13th fastest time on the super-softs.

22 cars are on track at the end of this session as the teams try to gather every last bit of data.

Button chips away at his lap time and is now up to ninth fastest. 14 laps completed in this session and 26 laps in total.

The chequered flag is out for the end of the session.

Hamilton's time at the top of the standings is safe as he finishes the session 0.054s faster than Alonso.

The top 13 were covered by less than a second, the top 19 by less than two seconds.

The rain stayed away for the whole session, which will have kept the teams happy and we are expecting more dry weather for qualifying tomorrow and the race on Sunday.

It should be a close and thrilling qualifying session. We'll be here to cover every lap as well as the morning practice session so make sure you join us again tomorrow.