ST. LOUIS — It’s called the “boiling water challenge” when someone tosses a cup of hot water into the air. When the boiling water meets the chilly air, it instantly becomes a mist or even snow. Videos of the trick often go viral on social media. But, the experiment can cause serious burns to anyone in its path.

There is a reason that videos of tossing boiling water in the air at freezing temperatures is going viral on sites like TikTok. The hot water suddenly has more water vapor than it can hold. So, the vapor turns into crystals by sticking to small particles in the air. This is how snowflakes start to form.

Is it true, however, that water at boiling temperatures freezes faster than water at room temperature? Is there a link between this and the pot-boiling-to-snow trick? No, it does not.

It is called the Mpemba effect. The liquid (usually water) that starts out hot can freeze faster than the same liquid that starts out cold, even though everything else stays the same. There are different ideas about how it works and what parameters are needed to make it work. 

Hot water being thrown into a minus degree day resulted in this heart shaped frozen masterpiece. The moment’s breezy conditions caused the heart shape to form.

A variety of tiny elements can influence how quickly something cools. Evaporation and convection currents must be considered.

Water in a hot or cold climate may interact with its surroundings in a variety of ways. The energy required to convert a liquid to a solid is vastly greater than the energy required to cool a liquid.

Despite being bundled up, accidents can still happen. Boiling water can cause serious burns. 

St. Louis Children’s Hospital says that it only takes a few seconds for children to be burned by boiling water. In fact, burns are the second leading cause of death in children under the age of five, owing to the fact that their skin is significantly thinner than that of an adult.

“Whereas adults could sustain a hand held in hot water for several minutes, young children can only have it in for a few seconds before getting burned,” explains Robert Kennedy, MD, emergency medicine specialist at St. Louis Children’s Hospital. “These few seconds can lead to lifelong scarring—or even death.”

The science behind the experiment might be tempting, but there really is no safe way to perform it. Back in 2019, the Loyola Burn Center treated eight people during the winter vortex. 

“We strongly warn people not to perform the boiling water challenge,” said Loyola burn surgeon Dr. Arthur Sanford in the article. “There is no safe way to do it.”