Tue Sep 23 03:00:00 UTC 2025: Here’s a summary and a news article rewrite of the provided text:

**Summary:**

The article, written by Adhip Agarwala, an assistant professor of physics at IIT Kanpur, explains the science behind how stamps stick to envelopes. It breaks down the fundamental forces of nature, focusing on the electromagnetic force and, more specifically, Van der Waals forces. The article explains that glue, made of polyvinyl-acetate (PVA), works because its molecules, while charge-neutral overall, exhibit temporary fluctuations in charge distribution. These fluctuations create attractive forces between the PVA molecules and the surfaces they’re applied to. Water is used to dilute the PVA initially, allowing it to spread, but evaporates to bring the PVA molecules closer together for adhesion. The author concludes by encouraging readers to appreciate the molecular interactions that ensure our mail arrives safely.

**News Article:**

**IIT Kanpur Physicist Explains the Science Behind Sticky Stamps**

**KANPUR, September 23, 2025** – Ever wondered how that little square of paper manages to stick to an envelope, braving postal journeys across the country? Adhip Agarwala, an assistant professor of physics at IIT Kanpur, unveils the fascinating science behind this everyday phenomenon in a recent article.

Agarwala delves into the world of fundamental forces, explaining that it’s not gravity or magnetism at play, but rather the subtle electromagnetic interaction known as Van der Waals forces. Glue, specifically polyvinyl-acetate (PVA), contains molecules that, while electrically neutral, exhibit fluctuating charges. These temporary imbalances create attraction between molecules, allowing the glue to adhere to both the stamp and the envelope.

The article further clarifies the role of water in the process. Manufacturers mix PVA molecules with water to prevent clumping, creating a liquid glue that can be spread easily. When applied, the water evaporates, bringing the PVA molecules closer together and maximizing their attractive forces.

“The next time you receive a letter,” Agarwala suggests, “whisper a word of gratitude to the molecules hard at work behind the stamp, which probably also kept it safely sealed all the way to your doorstep.” He encourages readers interested in learning more about the quantum mechanical origins of these fluctuating charges to consider studying physics.

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