The History and Uses of Dry Ice
What can produce fog at a Halloween party, keep foods and beverages cold during transport, assist in science experiments, and even preserve body parts for medical purposes? The answer, of course, is dry ice. This important product serves a variety of purposes today, and those who know all about it can use it safely and beneficially. Want to learn more about dry ice and what it does? Read this brief, helpful guide to become acquainted with all that dry ice is and has to offer.
Q: What is dry ice?
A: Dry ice is simply the frozen form of the common element known as carbon dioxide, which human beings exhale during respiration and which is essential to the health of plants all around the world. Dry ice is very cold, with an average temperature of minus 109.3 degrees Fahrenheit. Moreover, it is an unusual solid because it changes directly to a gas and not a liquid during a "melting" process known as sublimation.
Q: Who first observed dry ice and when?
A: Most historians agree that the French chemist named Charles Thilorier was the very first person to observe dry ice. In 1835 he was gazing into a metal cylinder that contained a great volume of liquid carbon dioxide in order to watch it evaporate. After the evaporation, there was a block of dry ice at the bottom of the cylinder. Prest Air Devices, which later became DryIce Corporation of America, was the first company to use dry ice commercially in the United States when in 1925 they built a factory to sell dry ice to railroads for cooling train cars.
Q: How is dry ice manufactured?
A: Today, dry ice is manufactured by releasing pressurized liquid carbon dioxide into expansion chambers. As this release occurs, the liquid carbon dioxide turns to gas and the temperature drops. About half of the liquid carbon dioxide becomes flakes of "dry ice snow," which are then pressed together in order to form blocks of dry ice. Dry ice is manufactured by a variety of companies and laboratories all around the country.
Q: What is it used for?
A: Dry ice is used for a variety of commercial, scientific, and entertainment applications. It can be placed into hot water to simulate fog during Halloween and on other occasions. Dry ice is also useful for science experiments and projects. It is also commonly used to transport frozen foods and even organs for medical transplants.
Q: Is dry ice hazardous?
A: The temperature of dry ice makes it a potential cause of frostbite when it is handled carelessly, so it is important always to wear protective gloves when handling a block of dry ice. There is also the danger of suffocation when it is allowed to sublimate in a closed, confined space, so dry ice should always be used in a well-ventilated area. Even so, food grade dry ice can be used to cool punch and other beverages, although the chunks of dry ice themselves must never be consumed by the drinkers.
Q: Where can I find more information on dry ice and its uses?
A: The Internet is a great resource for facts on dry ice. The following are some of the top sites online with more information about dry ice, its history, and its uses.
Cool Science: Dry Ice - Here are some fun experiments that can be performed using dry ice.
Cryogenic Milestones of Civilization - Included in this set of slides is a brief account of Charles Thilorier's discovery of dry ice.
Dry Ice - Some good information on dry ice as well as a video can be found on this page.
Dry Ice Info - This site, which is sponsored by manufacturers of dry ice, is a comprehensive guide to the history, composition, and applications of dry ice.
Dry Ice Safety - East Carolina University provides this resource on safely using and storing dry ice.
Dry Ice, Wetter Mars - Science News explains what a recent discovery of dry ice on Mars tells us about its climate.
Making Dry Ice - This is a PracticalPhysics.org article on making dry ice.
Melting Dry Ice - This page is a helpful overview on how dry ice melts and whether or not it can be used in beverages.
NWSFO: Dry Ice Safety - An extensive guide to dry ice safety, especially for kids, is found here.
What is Dry Ice - The New York State Department of Health has this good resource on dry ice.