Lightning strikes, lasting less than a half-millionth of a second, often scorch the skin but don't cause internal burns. Just as crucial, most of the electricity in a lightning bolt does not pass through the body. Rather, it dissipates over the skin in what's known as a flashover. Vernon Cooray, a lightning scientist at Uppsala University in Sweden, explains the phenomenon by contrasting the ways a human body and a tree react when struck.
Human-computer interaction (HCI) is the study and planned design of human and computer activities. HCI uses productivity, safety and entertainment to support and fulfill human-computer activities and is applied to various types of computer systems, including air traffic control, nuclear processing, offices and computer gaming.
Answer Wiki. User Interface is the thing that connects the user and the machine. It's what humans made, so that people can interact with the machine however they want to. The whole point is to make it simple for the user. The designers took examples from nature, and implemented them into the machine.