As temperatures soar across the UK, reaching 30°C, cars can become unbearably hot due to the greenhouse effect. Sunlight is absorbed by the dashboard, seats, and carpet through the windows, and these surfaces radiate trapped longwave heat, turning the cabin into an oven. However, mathematician and broadcaster Hannah Fry has a scientific trick to cool your car without air conditioning.
The 'Door' Technique
Fry's viral tip involves winding down one of the nearside windows and then rapidly opening and closing the driver's door several times. This action harnesses the laws of thermodynamics to flush out hot air. According to Fry, the temperature can drop significantly in just "two or three goes."
Explaining the science on her Instagram page, Fry said: "When you open and close the door quickly, the door sweeps out all the air in its way, creating an area of low pressure. This sets up 'bulk flow,' where all the hot, sweaty air inside the car is drawn outwards and replaced with fresh air from the other side."
When to Use This Tip
While air conditioning is standard in most new cars, this technique is useful if your AC has failed or you need a quick way to cool the car before a journey. Fry, who is also a contestant on the BBC's Celebrity Traitors, said her car felt "beautifully temperate" after trying this method.
Why Is It Getting Warmer?
The Met Office explains that the recent warming trend is due to a build-up of high pressure over the UK. As high pressure intensifies, air sinks and warms through adiabatic compression. This process can significantly increase surface temperatures, even if the original air mass from the Atlantic is not particularly warm. Temperatures are expected to drop later this week before a slight recovery on Saturday.
Other Cooling Tips
Experts at Which? suggest that electric fans may be more effective when pointed away from your body. During the day, aim the fan out of an open window to push hot air out and draw cooler air in. At night, when outside temperatures drop, reverse the fan to face inward to bring in cool air.
Remember, these tips can help you stay comfortable during the heatwave without relying solely on air conditioning.
