Hand Washing: A History
Washing hands was shown to be effective in preventing the spread of disease in 1847, when a doctor in Vienna found that an illness attacking women in childbirth in hospitals was caused by infection, and that physician hand washing drastically lowered incidence of the disease. This discovery led to more sanitation in hospitals, which made other infections decrease and led to our hand washing practices today [source: Centers for Disease Control].
Hand Washing Water Temperature
You've probably been told that it's best to wash your hands in hot water because it helps to kill bacteria, but that is actually not the case. Adult skin can begin to scald at 120 degrees Fahrenheit (49 degrees Celsius), but studies have shown that hands washed using water up to that temperature still don't remove bacteria [source: American Burn Association, World Health Organization].
Even though warm water isn't killing any germs, experts commonly recommend it for two reasons. The first and somewhat less scientific reason is that it's usually more comfortable to use than cold water. The second is that many modern soaps are designed to be most effective in warm water [sources: Hand Washing for Life, Christophersen].
Another reason to avoid using hot water is that it can remove natural oils from the skin. This loss of oils can lead to dryness or even cracking of the skin. In some cases, people may even begin washing their hands less to avoid making these symptoms worse [source: Starobin]. In other words, it's important to use water that is warm but not uncomfortable.
It's worth mentioning that modern soaps are still effective at colder temperatures; so, if you don't have access to heated water, it's still better to wash with cold water and soap than with no soap at all [source: Hand Washing for Life].
With the proper water temperature in place, you're ready to move on to methods for washing your hands. Time matters here, so read on to learn a simple method of ticking off the seconds while you suds up.