Roll Cloud Over Wisconsin

Roll Cloud Over Wisconsin What kind of cloud is this? A type of arcus cloud called a roll cloud. These rare long clouds may form near advancing cold fronts. In particular, a downdraft from an advancing storm front can cause moist warm air to rise, cool below its dew point, and so form a cloud. When this happens uniformly along an extended front, a roll cloud may form. Roll clouds may actually have air circulating along the long horizontal axis of the cloud. A roll cloud is not thought to be able to morph into a tornado. Unlike a similar shelf cloud, a roll cloud is completely detached from their parent cumulonimbus cloud. Pictured above, a roll cloud extends far into the distance as a storm approached in 2007 in Racine, Wisconsin, USA.

APOD keeping it down to earth!

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FPV servo controlled plane grabs epic vacation footage, puts old family videos to shame (video)

By the time winter rolls around, Alistair Roberts will probably remember his summer vacation a heckuva lot better than the rest of us. Why? Because he brought an FPV plane to record his mountain biking holiday in the Spanish sun. With a GoPro camera mounted on the servo-powered cradle, Alistair piloted the plane by moving his head and using a remote control -- all while streaming first person video from the cockpit into a pair of goggles. By pairing the high tech toy with another GoPro on his dad's mountain bike, and a stationary camera on the ground, Alistair was able to create a truly amazing vacation video from 1200 - 1500 feet in the air traveling around 20kmph (12mph) -- way cooler than any of the ones our dads recorded back in the day. Check out the video after the break.

[Thanks, @btudor]

Continue reading FPV servo controlled plane grabs epic vacation footage, puts old family videos to shame (video)

FPV servo controlled plane grabs epic vacation footage, puts old family videos to shame (video) originally appeared on Engadget on Sat, 10 Sep 2011 13:52:00 EDT. Please see our terms for use of feeds.

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What Supercritical Carbon Dioxide Looks Like

Shared by Frank
Dang yes; I would love to have one of these on my desk!! This is so cool. I really want to make one of these.

At extremes of temperature and pressure above a substance’s so-called critical point, the distinction between liquid and gas phases of that substance stops being meaningful, and the substance enters a homogeneous supercritical phase. For many substances, supercritical temperatures and pressures are difficult to achieve, and that’s doubly true if you’re hoping to achieve them under conditions that still allow for visual observation.

Carbon dioxide, however, has a fairly accessible critical point at about 90° F, 1100 psi, and thus supercritical carbon dioxide can and does have fairly routine industrial applications, notably the decaffeination of coffee. But the really cool part is that, at those temperatures and pressures, it’s not too hard to build a pressure vessel from transparent materials that will actually let you get a good look at a supercritical fluid. Which is exactly what Ben Krasnow—who is fast becoming my personal maker hero—has done.

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