Scientific Hack to Cool Your Car Instantly (No AC Needed)

Summer heatwave? Professional fluid-dynamics whiz, Dr. Hannah Fry from Cambridge University, has shared a clever cooling trick that doesn’t involve air conditioning

1. The Fluid-Dynamics Trick

• What to do:

1. 1. Roll down one of the rear windows (e.g. behind the driver).

   2. On the opposite side, quickly open and close the front door a few times.

• Why it works:

Opening the door creates a low-pressure area that sweeps out the hot, trapped air—and draws in cooler outside air via the open window. Fry calls it “bulk flow”. A clean, physics-backed move that sheds stifling air in just two or three swings.

2. Real-World Responses

• Viewers agree — the trick really works:
  • “You just improved my life more than Hannah knows.”
  • “This may be the best Reel I have ever seen.”

• Some say it’s useful at home too:

  • “I do this with my window and door in my tiny room… move a towel in giant circles …” 

3. Limitations

• Heatsinks matter: The intense heat stored in leather seats or dashboard plastics will rewarm the air quickly — especially in extreme climates
• Not a total fix: In places with 100 °F+ outside heat, simply open windows and drive until AC kicks in may be more effective

Opt for Fragrance-Free Products

To decrease the likelihood of inhaling toxic fumes, consider opting for fragrance-free cleaning products.

4. Pro Tips

• Combine with a reflective windshield shade to reduce heat buildup.
• If you have remote start or preconditioning, run your AC a few minutes before entering.
• Park in shade whenever possible — no trick beats that basic step.
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5. Try It Yourself!