Ice vs. Dry Ice
People often see both regular ice and dry ice as the same forms of ice. This is not surprising, because they really look the same when you just simply take a look at the two ice forms. Nevertheless, although both ice are used for cooling purposes, they are still very different from each other in various aspects.
Foremost, regular ice and dry ice differ in the way they are made, or in their overall structure. This means that regular ice is made by freezing water at freezing point temperatures. Dry ice, on the contrary, is made by the compression of CO2 (carbon dioxide gas) using very high pressures. Hence, regular ice, in its chemical form, regardless of its state of matter, is known as H2O, whereas dry ice is CO2 (the solid form of CO2 gas, literally).
Secondly, both ice types differ in the manner that they can be liquefied. With regular ice, you usually need more energy in the form of heat in order to melt it. 100 degrees Celsius, for example, will easily do the trick. Moreover, by lowering the overall atmospheric pressure, one can already melt dry ice. Nevertheless, dry ice goes from its solid state to its gaseous from in the process of sublimation.
In terms of freezing points, regular ice usually becomes an ‘ice’ when it reaches 32 degrees Fahrenheit, or about 0 degrees centigrade. Dry ice forms at negative 109.3 degrees Fahrenheit; a temperature that is a lot cooler than the freezing point of ordinary water.
Regular ice can also be used by humans in their beverages. Dry ice is usually used for cooling in shipping, and preserving fruits like grapes, most especially after a harvest; whereas regular ice is a coolant for regular foods and beverages. In this connection, it must also be made known that dry ice must not be used to cool your regular drinks, because it may prove detrimental to your health.
In summary, regular ice and dry ice differ in the following aspects:
1. In terms of chemical structure, ice is H20, whereas dry ice is CO2.
2. Regular ice can be melted by using heat, as opposed to lowering the atmospheric pressure to melt dry ice.
3. Ice can readily be ingested by humans, whereas dry ice is ordinarily not meant for ingestion (they are somewhat life threatening when eaten).
4. Dry ice needs a much lower temperature to become frozen as opposed to regular ice.