What is a diffuser and why has it courted so much controversy ahead of the first Grand Prix of the season in Australia?
Q: What is a diffuser?
A: An extension of the floor at the back end of a racing car, between the rear wheels.
Q: What is the purpose of a diffuser?
A: To gather and organize the high-speed air rushing under the car.
A: To reduce drag and increase downforce, thus increasing the speed and agility of the car.
Q: What is all the fuss about in Australia?
A: Three teams, Toyota, Williams and Brawn, have diffusers that work markedly better than those of the other teams. So their cars are markedly faster.
A: Because they have interpreted the regulations covering the shape and dimensions of the diffuser in a way that their rivals have not.
A: The interpretations vary; broadly speaking, they have increased the central area of the diffuser by incorporating it into the rear crash structure.
Q: Is this legal?
A: So far. Experts from the sport's governing body have been consulted on the designs, and the scrutineers in Australia have passed the cars of all three teams.
Q: What will happen next?
A: The six cars will race in Australia, and, most likely, in Malaysia, under protest, meaning that the results of the races may be subject to appeal.
Q: Why don't the other teams just copy the fancy diffusers?
A: The diffuser is a fundamental part of the design concept of a Formula One car. Change it, and you have to change a lot of other things too.
Q: Won't Ferrari and McLaren just throw money at the problem?
A: Yes, but these days that will not be sufficient to get them out of the woods. Testing is banned outside race weekends, so it will take a long time to evaluate new parts.
Q: In a nutshell?
A: Lewis Hamilton is stuffed for the next few races.
(this is from the telegraph uk)