What is lightning good for?
Listen to lightning: One / Two (requires Windows Media Player) A lightning stroke provides a good example of purpose in nature. Lightning may frighten us, but it also serves an important function: It helps provide our daily need of the element nitrogen. Nitrogen is the third most abundant element in the human body, and it must be renewed continually. We are actually surrounded by nitrogen, since it comprises 78 percent of the earth’s atmosphere. However, we cannot use the nitrogen in this molecular, gaseous form; nitrogen gas has a strong covalent bond that our bodies cannot break down. Instead, nitrogen must first be taken up by plants as part of the food chain. There are two major ways in which nitrogen becomes part of vegetation. First, certain plants are able to absorb or “fix” nitrogen through their root systems. These plants are called legumes and include clover and peas. Legumes are distinguished by nitrogen-fixing bacteria that live inside their root nodules. These bacteria cha
