Question

How does an instant cold pack get cold so quickly?.

Answer 1

An instant cold pack gets cold due to an endothermic reaction when ammonium nitrate dissolves in water, absorbing heat and creating a sensation of cold.

Step-by-step explanation:

An instant cold pack becomes cold so quickly due to an endothermic reaction occurring within the pack. When the pack is activated, typically by squeezing it to break an internal barrier separating two components, a salt such as ammonium nitrate dissolves in water. The process of dissolution for ammonium nitrate is endothermic; it absorbs thermal energy from the water and, consequently, from the surrounding environment, including the user's body if applied to the skin. This absorption of heat results in the sensation of cold.

Answer 2

Here is how

Instant cold packs are actually made up of two bags inside. ... When you shake or hit the pack, the internal bags break, causing the two substances to mix. This leads to an endothermic reaction which causes the pack to turn cold for several minutes.