(CNN) It looks cool -- throwing boiling water into the air and watching it instantly freeze in supercold weather -- but don't do it.

The boiling water challenge that has gone viral in the past few weeks as the polar vortex gripped a large part of the United States may be an interesting science experiment, but hospitals say it's also sending people to the emergency room.

Eight people who took part in the challenge have been treated at the burn center of Chicago's Loyola University Medical Center since the deep freeze happened last week, spokeswoman Chris Vicik said.

They had injuries to their "feet, arms, hands, face, and varying degrees of burns, as well," she said.

One person sought treatment at the University of Iowa Burn Treatment Center in Iowa City, spokesman Tom Moore said, and Hennepin Healthcare in Minneapolis said a "couple" of people were treated there in recent weeks.

Read More