Liquid nitrogen is around -195.8°C (-320.4°F), i.e. very, very cold. While it’s usually used to freeze warts or for cryopreservation, YouTuber Grant Thompson – "The King of Random" – wondered what would happen if you put it in a balloon.
You might expect a fairly lackluster reaction of the balloon fraying or cracking with the intense chill, but the results are actually far more interesting. As you can see in the video below, the balloon starts to inflate itself. This happens because the nitrogen has a boiling point of -195.8°C, meaning it quickly turns from a liquid into a gas at Earth-bound temperatures. That’s also why you can see it bubbling away on the patio after the balloon's inevitable passing.