Q) What's the fastest insect?
Ellie Kunkel, Savage, Minnesota
A) Given the vagaries of wind speed and the fact that insects zig and zag, it's very hard to measure the swiftness of flying bugs. But there's someone on the case: entomology professor Thomas Walker, who, with his students at the University of Florida, undertook a massive study of bug trivia for the online Book of Insect Records. On the subject of flight speed, they turned to the most exhaustive research to date, that of T. J. Dean, a physics postgrad at the Australian Defence Force Academy. Dean's 2003 report, which drew upon reams of peer-reviewed studies, found that the "highest reliably measured airspeeds," free of wind influence, belong to the desert locust (the ones that plague the Old Testament), which moves at 21 miles per hour—about like an Olympic sprinter. But there may yet be an undocumented speed king out there: Many have odds on the Australian dragonfly, but so far it's eluded the radar gun.
Q) If you can't compost, is it more ecologically sound to put food down the garbage disposal or send it to the landfill?
Peter Keppler, Watertown, Massachusetts
A) It depends on what the local waste-processing plant does with your crud, says Jeremy O'Brien, a North Carolinabased engineer with the Solid Waste Association of North America. If you put your waste down the disposal, it flows, along with household sewage, to a plant where it gets separated into thick sludge and treated wastewater. The sludge is placed in tanks and heated until anaerobic bacteria consume all the organic materials in it. This produces methane, a gas that some facilities turn into electricity to run their operations. Many plants also sell the dried sludge cakes as fertilizer or use them for fuel. If your plant puts sludge to use in one of these ways, stuff that grub down the disposal—it's more earth-friendly than having it hauled away by a diesel truck. But if it still sends sludge to the dump, you're better off saving the plant (and those hardworking bacteria) all that energy by trashing it yourself.
Q) Do people sweat when they swim?
Jami Kei Markle, Grand Marais, Minnesota
A) That's affirmative, says Louise Burke, a dietitian at the Australian Institute of Sport, in Canberra. Burke recently published a study in which 64 swimmers and water-polo players were weighed before and after their workouts, and found that they lost an average of 14 ounces of sweat per hour—much less than the 50 ounces leaked by a typical marathoner, but plenty of drippage all the same. Of course, since evaporation doesn't occur underwater, perspiring—which is the body's way of releasing excess heat generated by exertion—doesn't do much good for swimmers. But they shouldn't sweat it. A body moving in water loses heat at a rate 60 to 80 times faster than in air, so direct heat transfer, mostly through convection, cools swimmers down as they churn.