Where did Harriet Tubman go when she escaped from slavery?
Evelyn Ruth Maxey, Houston, Texas
Definitive information about her early life remains elusive, says Christopher Wilson, director of the African-American History Program at the National Museum of American History. But most sources suggest that when Tubman, in her late 20s, fled from the Edward Brodas plantation in Maryland’s Dorchester County in 1849, she went to Pennsylvania; an early biography, by her friend Sarah H. Bradford, says she reached Philadelphia. Tubman returned to Maryland the next year to smuggle her niece and her niece’s children to freedom—and kept returning as late as 1860, for as many as 19 trips, during which she helped free 300 slaves.
How are spiders able to shoot their webs over long distances? A web in our backyard measures about 12 feet.
Charles Lusk, Leawood, Kansas
Spiders do not actually “shoot” webs, says Jonathan Coddington, senior scientist at the National Museum of Natural History. They draw their silk out of their spinnerets, or silk-producing organs, with their fourth legs until it catches a breeze, which carries it to another spot; now the spider can walk across that line, and may draw out additional ones as she goes. And so on. Thus a spider web can span a distance of 30 feet or more. A web spun by a Darwin’s bark spider in Madagascar was measured at more than 80 feet.
I recently read that large numbers of Irish men, women and children were exported to the United States as slaves. Is that true?
Eugene Zysk, Roseville, Michigan
Not really. In the early Colonial years, says Fath Ruffins, curator at the National Museum of American History, some Europeans, including Irish people, could end up in involuntary servitude as punishment for a crime. That practice died out as slavery was limited to Native Americans and Africans. A greater number of poor Europeans, including the Irish, were brought to the Colonies as indentured servants. Their servitude was limited to a contractually set period of time, but they had no legal rights and were sometimes treated as cruelly as slaves—and sometimes ran away. Even Boston-born Ben Franklin, indentured to his much older brother to learn printing, fled and moved to Philadelphia.
Can you use a compass to navigate at or near the North Pole?
Lawrence Bricker, Silver Spring, Maryland
That would be impractical, says Roger Connor, curator at the National Air and Space Museum. At the geographic or “true” North Pole—where the lines of longitude converge—a compass points to the magnetic North Pole, several hundred miles south, near Ellesmere Island in Canada. At the magnetic North Pole, a compass held flat points at random; held on edge, it points straight down. In the 1950s the Inertial Navigation System, a network of sensors and a computer, enabled polar navigation without magnetic tools, and in the 1990s, GPS—the satellite-based global positioning system—made it simpler and less expensive.