Why does poison ivy make us itch?
— Eric Hunleth, Portland, Maine We're allergic to it! About 80 to 90 percent of people are allergic to urushiol, the oil in poison ivy, poison oak and poison sumac.
What are the biggest misconceptions about tsunamis?
— Melissa Mandel, Hilo, Hawaii One is that a tsunami is a single wave and once it has passed, the event is mostly over. Rather, a tsunami is a series of waves that occur from minutes to hours apart. Another mistaken belief is that a tsunami looks like a gigantic curling wave. But most often, it looks like an enormous tide. No wonder tsunamis are frequently called "tidal waves."
Send questions to firstname.lastname@example.org