Wednesday, 22 May, 2013

How does tornado season vary across the United States? Tornado season begins as early as late February or early March in northern Texas and Oklahoma, the southern portion of Tornado Alley, where the tornado threat remains through most of May. By early June, the greatest threats tend to lie to the north, in Kansas and [...]

Whack that baseball! When you hit a baseball, speed, angle and air resistance all affect how far it travels. Balls hit too low quickly return to Earth; balls hit too high travel a long way vertically, but not far horizontally. Can you find the “sweet spot” where horizontal travel is greatest. Can you find the [...]

The curious growth of a snow crystal Temperature and humidity affects the shape of snowflake crystals. The temperature of formation determines the original crystal shape. Large (“dendritic”) flakes grow best between -10° and -12° C. Plates grow at warmer or colder conditions. Humidity — water vapor pressure in the cloud — affects the growth rate [...]

Light on Lightning! Danger! Sound moves about 1,000 feet per second through air. To find out how far away the storm is, start counting “1 one-thousand, 2 one-thousand…” when you see a flash. Five counts, or five seconds, equals about one mile. But lightning bolts don’t come just from the center of the storm. To [...]

A tornado that’s 500 meters in diameter looks a lot more ominous than the average twister, which is “only” 150 meters across. All other things being equal, larger tornadoes are more damaging, but size is not related to wind speed. Instead, wind speed increases along with the difference between atmospheric pressure inside the funnel, and [...]

Rainbows are one of the wonders of the natural world: But why do you sometimes see one rainbow, and other times a double? Why do you always see rainbows with your back to the sun? How do they really work? Operate your own rainbow, then find out! OPERATING INSTRUCTIONS: CHOOSE YOUR ‘BOW: • Primary shows [...]