<P> The salt and ice challenge is an Internet phenomenon wherein participants pour salt on their bodies, usually on the arm, and ice is then placed on the salt . This causes a "burning" sensation, and participants vie to withstand the pain for the longest time . The challenge can be recorded and posted on YouTube or other forms of social media . </P> <P> The mixture of ice and salt creates a eutectic frigorific mixture which can get as cold as − 18 ° C (0 ° F), much colder than ice alone . This repeatable cooling reaction was used to calibrate the Fahrenheit temperature scale . </P> <P> The salt and ice challenge can quickly cause second - and third - degree injuries similar to frostbite or burning yourself with the metal end of a lighter . Due to the numbing sensation of the cold and possible nerve damage during the stunt, participants are often unaware of the extent of any injuries sustained during the challenge . Skin discoloration from the challenge may remain after the challenge has been attempted . </P>

Ice and salt on skin why does it burn