April 3, 2012
Reader questions have a way of bringing out some of the best of Smithsonian Institution knowledge. In the video above, curator Evelyn Hankins gives us a better understanding of the materials used to make contemporary art. And thanks to your questions, we learn that Ben Franklin’s kite experiment may have been a bit of a tall tale, but that he did invent the lightning rod. How bees make honey is another sweet story. And finally, when you snuggle up with your cat and hear that familiar purr, don’t you wish you knew how they do that? You asked and we answered. Hey, this is fun: send us more.
What is lightning, and did Benjamin Franklin really fly a kite in a thunderstorm?
Janice Lee, Bethesda, Maryland
Thanks to Franklin, we know lightning is simply a discharge of atmospheric electricity—but historians still debate whether he conducted the kite experiment.
That debate, however, misses a more important story. In 1749, Franklin published a proposal for an experiment to prove that lightning and electricity are the same; that experiment involved erecting a tall metal rod to accumulate atmospheric electricity. In 1752 a team of French experimenters became the first to try it. Franklin’s experiment gained credibility because the French scientists—men of standing, not some British colonist—lent it their imprimatur. Franklin would apply the knowledge collected in this experiment to invent the lightning rod.
Steve Madewell, Interpretive Exhibits Coordinator
National Museum of American History
How do honeybees make honey?
Elsie Talbert, Los Angeles, California
Foraging bees siphon nectar out of flowers with their proboscis (tongue), store it in their crop (“honey stomach”) and feed it to hive bees when they return to the hive. The hive bees “process” the nectar with enzymes and regurgitate it into empty waxen cells as honey. Since nectar is more than 70 percent water, hive bees will fan the developing honey to encourage water evaporation. Bees make honey to feed themselves when little or no nectar is available (e.g., winter). In temperate zones, honeybees remain in the hive unless it’s 54 degrees Fahrenheit or warmer; while in the hive they consume the honey they made over the summer.
Nathan Erwin, Entomologist
National Museum of Natural History
How do cats purr?
Stacey Flynn, Germantown, Maryland
As cats inhale and exhale, the muscles of the larynx alternatively dilate and constrict the glottis; that movement of the glottis produces sudden separations of the vocal folds, or cords; those separations produce the purring sound. The muscles that move the vocal folds are driven by a free-running neural oscillator that generates contractions and release every 30 to 40 milliseconds. Except for a brief transition pause, purring is produced during both inhaling and exhaling and sounds like a continuous vocalization. Purring is nearly ubiquitous among the cats, but it is not heard in lions and tigers.
John Seidensticker, Conservation Biologist
Smithsonian Conservation Biology Institute, National Zoological Park
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