A viral car cooling hack, demonstrated by Capital FM presenters and endorsed by mathematician Professor Hannah Fry, claims to cool a sweltering vehicle faster than air conditioning. The method, which relies on fluid dynamics, involves winding down one rear window and rapidly opening and closing the driver's door four times.
How the Hack Works
Presenter Sian Welby explained the tip on Capital FM, originally seen on Professor Fry's social media. She said: "So you're in the driver's seat. You're going to wind down the window of the back left seat. Then you're going to get out of your driver's seat and just open and close the door [four times.] You get back in the car, it's cool."
The trick uses a principle called bulk flow. Professor Fry, in her own YouTube video, elaborated: "When you open and close the door - especially if you do it quickly - the door sweeps out all of the air that's in its way, creating this area of low pressure... and then that sets up something called bulk flow which is where all the hot, sweaty, horrible air inside the car is drawn outwards." The only replacement air comes from outside through the open window, cooling the interior rapidly.
Scientific Basis and User Confirmation
The method is based on fluid dynamics, a branch of physics. Fry joked that practitioners might look "like a bit of an idiot" but assured it works. In the video's comments, users confirmed its effectiveness. One wrote: "I used to do this without knowing the science behind it-- it just seemed like the thing to do and it helps." Another said: "Been doing this for 20 years with the blind belief that it’s better than just opening all the windows. Thanks for the scientific pardon." A third added: "This is a top tip, I've been doing this for years and can absolutely confirm it works as described."
Context: UK Heatwave
The tip comes as the UK experiences an intense heatwave, with a red alert for hot weather covering over 50 areas. Cars can become extremely hot in such conditions, making the hack timely for drivers seeking relief without relying solely on air conditioning.
