This simple plastic bag trick left Anand Mahindra wishing for a different physics teacher

What if one breath could inflate an incredibly long plastic bag in seconds? That’s exactly the kind of classroom moment that could have made physics unforgettable. A viral video demonstrating a clever science trick has now caught the attention of Anand Mahindra, who couldn’t help but reflect on his own school days. The clip, built around Bernoulli’s principle, turns what many remember as a dry textbook concept into something surprisingly fun and instantly visual.

The now-viral clip shows a man attempting to fill an incredibly long yellow plastic bag with air. He begins by asking viewers a simple question: can it be filled with just one breath? To demonstrate, he first tries the conventional method. He gathers the open end of the bag into a narrow opening, places his mouth directly on it, and blows. The result is underwhelming. Despite the effort, the bag does not fill up in a single breath, nor after 10. Then comes the twist.

Inflating plastic bag using Bernoulli's principle

He deflates the bag completely and announces that he will now use Bernoulli’s principle. This time, instead of sealing his mouth around the opening, he holds it slightly away from the bag and blows air toward it. As he explains, blowing air across the opening creates a low-pressure area inside the bag. The surrounding air gets pulled in along with the stream of air from his breath.


The effect is instant. With just one breath, the flat yellow plastic bag inflates dramatically, drawing in far more air than expected.



The same principle can be used to move air efficiently. For example, on a hot summer night without air-conditioning, if someone wants to push hot air out of a room using a standing fan, placing the fan directly at the window may not be the most effective approach. Instead, backing the fan up slightly from the window allows it to push air out while also pulling surrounding air along with it, increasing airflow.

Anand Mahindra reacts

Reacting to the video, Anand Mahindra took to X to share how he wished his school physics teacher had been as animated and creative as the man in the video. He noted that Bernoulli’s principle would have been far more exciting instead of becoming just another concept to memorise. He also added that even in the age of AI, creative teaching will always have a space.


What could have been just another science lesson turns into a moment of surprise. And for many watching, including Anand Mahindra, it’s a reminder that sometimes all it takes is one clever demonstration to make a principle come alive.