Budding scientists, engineers and doctors lined up to try surgical robots from Intuitive Surgical at a science festival in Washington, D.C., over the weekend. Scott Hensley/NPR hide caption

itoggle caption Scott Hensley/NPR

People who are interested in and paying close attention to each other begin to speak more alike, a psychologist says. iStockphoto.com hide caption

itoggle caption iStockphoto.com

A man gathering firewood to sell cuts down mangrove trees in the coastal area of Medan city on Indonesia's Sumatra island on Jan. 31. The country, which has one-quarter of the world's mangroves, is losing them at a rate of 6 percent a year. The coastal forests play important ecological and environmental roles. Suntanta Aditya/AFP/Getty Images hide caption

itoggle caption Suntanta Aditya/AFP/Getty Images

Noah Stewart shelters in the closet just 15 minutes before an April 2011 tornado demolished his house. Wearing the helmet may have saved his life, one doctor says. Courtesy of the Stewart family hide caption

itoggle caption Courtesy of the Stewart family

Germany plans to take all of its nuclear power plants offline by 2022, which means coal-fired power plants like the Kraftwerk Westfalen, in Hamm, Germany, will be a key component of the country's energy infrastructure. Lars Baron/Getty Images hide caption

itoggle caption Lars Baron/Getty Images