It is made more complicated this year by the presence on many cars of the F-duct aerodynamic device, pioneered by McLaren but since adopted by several other teams.
"If you don't have aerodynamic features - like the F-duct or the exhaust blown diffuser - then you want to implement them, so you develop them at home, build them on to the car and test them on the race weekend, " explained Schumacher, who was used to unlimited testing in his previous Formula 1 career.
Second practice then saw Hamilton abandon the F-duct, which increases speed on the straights, while Button completed the session with the aerodynamic aid in place.