{"id":69154,"date":"2026-11-02T04:29:54","date_gmt":"2026-11-01T19:29:54","guid":{"rendered":"https:\/\/phys-edu.net\/wp\/?p=69154"},"modified":"2026-11-02T04:29:54","modified_gmt":"2026-11-01T19:29:54","slug":"just-wipe-on-dish-soap-and-window-condensation-disappears-the-science-of-spreading-water-droplets","status":"publish","type":"post","link":"https:\/\/phys-edu.net\/wp\/?p=69154&lang=en","title":{"rendered":"Just Wipe on Dish Soap and Window Condensation \u201cDisappears\u201d?! The Science of Spreading Water Droplets"},"content":{"rendered":"

Hi, I’m Ken Kuwako, your Science Trainer. Every day is an experiment.<\/strong><\/span><\/p>\n

You pull back the curtains in the morning and the window is dripping wet. Before you know it, the area beneath it has started to look faintly black and grimy… sound familiar? Winter condensation, if left alone, can turn into mold. But here’s the claim: just dilute some kitchen dish soap and wipe it on your windows, and you can stop condensation.<\/strong> Is that really true? I put it to the test.<\/p>\n

Condensation shows up every winter. If it leads to mold, you end up with blackened window frames and spores floating around in the air, which isn’t great for your health. The good news is that there’s a simple trick to keep it at bay: mix up a diluted solution of dish soap and spread it on your window.<\/p>\n

First, Let’s Recreate Condensation with an Experiment<\/h3>\n

Here’s a metal cup filled with water. When I drop ice into it, the air around the cup gets chilled, and its saturation vapor pressure drops. In plain terms, the air can hold less water vapor than before. The water vapor that no longer fits in the air turns back into liquid, forming droplets on the outside of the cup. That’s condensation.<\/p>\n

It’s the same thing that happens when a glass of iced tea mysteriously ends up wet on the outside. Condensation occurs when warm air meets a surface that’s been cooled down. In winter, we heat our rooms and run humidifiers, so the indoor air is packed with water vapor. Then that air touches window glass chilled by the freezing air outside, and the same thing happens: your window ends up soaking wet.<\/p>\n

Comparing a Cup with Soap on It<\/h3>\n

This time, I coated just part of the cup’s surface with diluted dish soap.<\/p>\n

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Then I chilled the cup in the same way, and look at that!<\/p>\n

The coated and uncoated parts ended up looking completely different when it came to how the droplets formed.<\/p>\n

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Zoom in and the difference is obvious. The coated area has almost no water droplets at all.<\/p>\n

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You can also watch the experiment in this video.<\/p>\n