Which cooling technology provides a lack of cooling shock to the wearer's system?

• A. Forced air cooling
• B. Liquid cooling
• C. Phase change cooling
• D. Evaporative cooling

Answer: (C)

Phase change cooling uses materials that absorb heat as they change phase (for example, from solid to liquid) at a nearly constant temperature. Because the heat is taken up at that steady temperature, the wearer experiences a stable, gradual cooling rather than a sudden drop in temperature. This minimizes cold shock to the body. Other methods can deliver cooling more abruptly or in a less predictable way—forced air can feel icy if the air is very cold or change quickly; liquid cooling can cause cold spots or rapid changes when flow starts or stops; evaporative cooling depends on humidity and conditions, which can lead to less predictable cooling. The steady, plateau-like cooling from phase change materials keeps the wearer more comfortable and reduces shock.