Water that is heated to 100 degrees Celsius, or 212 degrees Fahrenheit, reaches its boiling point and is converted to steam. This is caused because kinetic energy in the form of heat is being added to the water. Once a liquid reaches its boiling point, the heat energy begins to change the state of the liquid. Once the state has changed, added heat will cause the temperature to rise again. The rate at which the temperature changes is the specific heat. When energy is added to water molecules, it causes them to move faster and eventually leave the water and enter the air. In the air, still moving quickly, they run into each other and into the other molecules in the air which causes them to move apart from each other.
Inside a volcano, steam is forming underneath rock. The molecules are moving so fast that they push the rocks apart. Geysers are natural fountains that can shoot boiling water and steam hundreds of feet into the air. Some of these eruptions last just minutes, while other geysers last days. Some erupt violently and then are quiet for years. Geysers are rare because several conditions need to be met for them to occur. These conditions are abundant water, volcanic heat, special rock called geyserite and a unique underground shape. If some of these conditions are not present, fumarole steam vents will likely form. These are steam vents that occur when less water is present. As the liquid comes to the surface, it is boiled off and steam can be seen coming from a hole in the ground. Hydrogen sulfide often gets mixed in with the steam, causing these steam vents to smell strongly of sulfur.
The power in steam has been harnessed in many ways. The first known device moved by steam pressure was the aeolipile, developed by Hero. It consisted of steam jets spinning a rotating ball and had no practical use. The 17th century saw the development of costly, limited devices which used steam power until useful pumps for mining were created in 1700. The late 18th century brought improved steam engine designs. These were timely as the Industrial Revolution created a need for practical power sources. Factories could now be built anywhere, whereas before steam power they relied on wind or water power and were restricted to certain locations.
Steam has long been used to heal and rejuvenate the skin. Steam saunas boost skin circulation by increasing pulse by 30 percent and raising the skin temperature to about 104 degrees. Recent research indicates that steam can alleviate acne, moisturize and protect skin. Steam is now being used in the medical field as well. Uptake Medical in Seattle, Washington has developed bronchoscopic thermal vapor ablation, a technology that delivers steam to the lungs of patients with emphysema in order to relieve symptoms.