Table of ContentsOverviewWhat are instant hot and cold compresses?Brief History of Heating CompressesBrief History of Cold CompressesThe use of cold for therapy has evolved in 3 stages:Uses and Benefits of Hot PacksThe Chemistry of Instant Hot and Cold PacksCalcium Chloride: Magnesium SulfateHigh Temperature CrystallizationUrea: CO(NH2)2Environmental Implications Environmental Concerns of Instant Hot and Cold PacksOverviewWhat is it?Brief historyUsesHow it worksEnvironmental benefits and concernsCurrent research and future directionWhat are instant hot and cold packs Packs: plastic bags containing different chemical compoundsSay no to plagiarism. Get a tailor-made essay on “Why violent video games should not be banned”?Get the original essay When pressed, hot compresses create an exothermic reaction releasing heat. Cold compresses create an endothermic reaction that absorbs heat and becomes cold. They can be used for different types of injuries or pains Presenter Notes: Instant hot and cold packs are plastic bags (similar to that used for an ice pack), which contain different chemical compounds. When pressed, hot compresses instantly create an exothermic reaction that releases heat, while cold compresses instantly create an endothermic reaction that absorbs heat and becomes cold. These are generally used to treat various types of injuries and pain. Brief History of Heat Packs In Japan, around 1603-1868, many heated stones were wrapped in cloth to provide a soothing application of heat. These early "heat packs" required an external heat source such as fire, so they were not very practical. In 1911, the first electric heating pad (“El Warmo”) was designed by Earl Richardson. Problems arose such as the risk of fire. This was due to old threads coming into contact with fabric. heat source or electricityPresenter Notes: In Japan, from the early 1600s to the mid-1800s, a popular method of heat therapy involved heating stones using an open fire and wrapping them in a cloth to apply them to the affected area. Although this method was effective to some extent, it required fire as a heat source, which was not available at all times, making this method impractical. It wasn't until 1911 that Earl Richardson designed the first electric heating pad which he called "El Warmo". This form of thermotherapy was more practical than the previous one and more accessible since it only required electricity. However, problems did arise, such as old threads coming into contact with fabric, creating a fire hazard. This led to the development of an instant heat pack that required no external heat or power source. Brief History of Cold Compresses The use of cold for therapy evolved in 3 stages: 19th century - Natural ice was used for cold therapy (e.g. snow to numb soldiers). in 1812)1890s to 1950s - Experiments began with substitutes for natural ice 1950s to present - Chemical cold compresses were developed Speaker Notes: The Use of Cold Therapy for Swelling , injuries and numbness dates back to the 19th century during war. At that time, doctors usedice or natural snow to numb the soldiers. From there, cold therapy evolved and people began using substitutes for natural ice. Ice cream was made at home using an ice cube tray and placing the ice in a cloth or plastic bag. After this, gel ice packs were created which had to be frozen before use. And finally, chemical cold packs have been developed that are instantaneous, requiring no external source of cooling. Uses and Benefits of Hot Packs Heat increases blood flow to restore movement to injured tissues. Reduces joint stiffness and pain. Relaxes tense muscles, causes tissue relaxation. tension or spasmInstantly warmPortable and easy to useSlide 9: Uses and benefits of cold compressesReduces blood flow to a particular area, thereby reducing inflammation and swellingMay temporarily reduce nerve activity, which may relieve painInstant, ready to go 'useGood in case of emergencySmall, portable and safeThe chemistry of instant hot and cold packsEndothermic and exothermic reactions occur as a result of salt dissolving in waterThe salt dissociates, causing the hot and cold packs to release heat heat absorption by cold compresses. How this happens depends on the chemicals usedSpeaker Notes: Most instant hot and cold packs work by dissolving some sort of salt in water. When this dissociation occurs (see figure 1 for example) endothermic or exothermic reactions take place. The chemical compounds used differ depending on the brand and type of hot and cold packs. Calcium Chloride: Presenter Notes: The simplest hot packs use calcium chloride. When the instructions on the hot compress are followed (e.g. "press here"), the water mixes with calcium chloride, which then dissociates into its Ca2+ and Cl- ions (Figure 2), initiating the release of heat as The potential energy diagram for this exothermic reaction shows. The temperature of the hot compress can reach up to 90 degrees almost instantly. Magnesium SulfateSpeaker Notes: Magnesium sulfate also produces a large amount of heat when dissolved in water. The process that takes place inside a warm compress containing magnesium sulfate is very similar to that of calcium chloride. Inside a hot pack containing magnesium sulfate, there is a small pouch filled with water and it is surrounded by magnesium sulfate in crystalline form. When the small pouch is broken, the crystals begin to dissolve in water (Figure 3), causing an exothermic reaction as shown in the potential energy diagram. Crystallizes at high temperatures High boiling and melting points Speaker Notes: The process that occurs in a hot compress containing sodium acetate is slightly more complicated than the previous two, however it is more effective since they are reusable. Since sodium acetate freezes at 54 degrees and will remain in solution at temperatures below its crystallization point. These heat packs contain a solution of sodium acetate and water along with a small metal disc insulated from the solution. To initiate crystallization, pressure can be applied to the small metal disc, causing a few molecules to crystallize. As a result, the rest of the molecules jump and then solidify, raising the temperature to 54 degrees (eg figure 5). These types of heating compresses.