Some products contain iron filings that will react with air to release what type of energy?
spectral
physical
mechanical
thermal
Hikers, campers, and other outdoor folks take advantage of chemical reactions to keep their hands warm. Small containers of chemicals can undergo reaction to generate heat that can be used to avoid frostbite. Some products contain iron filings that will react with air to release thermal energy. These types of warmer cannot be reused. Other systems rely on heat being released when certain chemicals crystallize. If the warmer is placed in very hot water after use, the system can be regenerated.