Smoking Fingers Trick

The smoking fingers trick is a simple yet impressive science "magic" trick that you can perform using nothing more complicated than a box of matches. You rub your fingers together, producing smoke. There's no heat or fire, though. This trick is based purely on chemistry.

Smoking Fingers Video | Smoking Fingers Instructions

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What Are the Van Allen Radiation Belts?

You probably have heard of the Van Allen radiation belts, sometimes just called "radiation belts", but might be unclear what they are or what they do. That's okay, because there is a lot that scientists don't understand about them. For example, while the radiation belts are known to shrink and expand in response to the solar wind and solar storms, we can't predict how the belts will react to a given event. Sometimes the belts don't seem to change at all in response to what appears to be the same type of event that caused them to react in the past. Sometimes they swell to include regions containing satellites and the International Space Station... learn more

How To Watch the Radiation Belt Storm Probes Launch | Why You Should Care About the Radiation Belts

 

Vicious cycle boosts use of browser-based ad blockers

Computerworld - Nearly one in four browsers are armed with an ad-blocking tool, reducing revenue at free-content websites, an Irish company said today.

The popularity of ad blocking -- driven by users' frustrations with intrusive, distracting or just-plain-ugly-and-noisy ads -- threatens the free-for-all model of the Internet, said PageFair, a company that's helping content publishers audit the problem and try to stem some of the bloodletting.

"It's a vicious cycle," said Neil O'Connor, CEO of Dublin-based PageFair. "Ads are becoming more aggressive to capture eyeballs, but that forces more people to install ad-blocking software. It's a lose-lose situation."

But without ads and the revenue they generate, most content publishers cannot sustain operations. Sans ad revenue, the only options are to charge for access -- the path taken by publishers like the Wall Street Journal and the New York Times -- or fold the tent.

[Note: Computerworld, like the vast majority of content creators, relies on ad revenue.]

PageFair mined its data from the past 11 months and found some surprising nuggets about ad blocking.

"We started this because we were a publisher ourselves, in the game space," said O'Connor. "We wanted to know how many of our users were dropping out by installing ad blockers, and thought it was maybe as high as 10%. But we found that 30% were blocking our ads. That was shocking to us."

On average, 22.7% of the users who browsed to the several hundred sites monitored by PageFair since September 2012 used an ad blocker, but the range was very wide, from just 1.5% to 65%.

The more technically savvy a site's audience, the more likely they will block ads, said O'Connor. Game-related websites, for instance, deal with an average ad-blocking rate of 30%, the highest of any category. More mainstream websites, however, have a lower percentage of ad-blockers: The average for travel sites is around 5%.

"The severity of ad blocking on a given site is positively correlated to the technical ability of its audience," said O'Connor in a report PageFair published Wednesday (download PDF).

That's because browser ad blocking relies on add-ons, which not all users are comfortable installing, or even know exist. AdBlock Plus, which offers add-ons for Chrome, Firefox, Safari, Opera, and most recently, Internet Explorer, is the best known.

Firefox users block ads more than those running any other browser, said O'Connor, perhaps because the Mozilla browser has long trumpeted its add-on ecosystem. Also, AdBlock Plus has supported Firefox the longest of any browser.

According to PageFair's data, 37% of Firefox users block ads. Google's Chrome took second place with a 30% blocking rate. IE's rate was miniscule, under 1%.

Corroborating PageFair's numbers is difficult. A May 2012 analysis (download PDF) by ClarityRay, which like PageFair works with companies to counter ad blocking, pegged the percentage of browsers running blockers at 9.3%. But the two companies agreed on many points, including Firefox users' greater interest in ad blockers and technical sites' increased likelihood of being blocked.

Small and midsize businesses are moving to the cloud to host their communications capabilities. Learn how enterprise-quality phone benefits, online management, conferencing, auto attendant, and ease of use are built into a system that is half the cost of a PBX.

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Why Leaves Change Color in the Fall

The official start of fall is the autumnal equinox. This is when the sun crosses the celestial equator, making day and night essentially the same length. While you might not know the date of the autumnal equinox every year, you know fall is approaching because leaves start to change colors.

When leaves appear green, it is because they contain an abundance of chlorophyll. There is so much chlorophyll in an active leaf that the green masks other pigment colors. Light regulates chlorophyll production, so as autumn days grow shorter, less chlorophyll is produced. The decomposition rate of chlorophyll remains constant, so the green color starts to fade from leaves. At the same time, surging sugar concentrations cause increased production of anthocyanin pigments. Leaves containing primarily anthocyanins will appear red. Carotenoids are another class of pigments found in some leaves. Carotenoid production is not dependent on light, so levels aren't diminished by shortened days. Carotenoids can be orange, yellow, or red, but most of these pigments found in leaves are yellow. Leaves with good amounts of both anthocyanins and carotenoids will appear orange. Leaves with carotenoids but little or no anthocyanin will appear yellow. In the absence of these pigments, other plant chemicals also can affect leaf color. An example includes tannins, which are responsible for the brownish color of some oak leaves.

Temperature affects the rate of chemical reactions, including those in leaves, so it plays a part in leaf color. However, it's mainly light levels that are responsible for fall foliage colors. Sunny autumn days are needed for the brightest color displays, since anthocyanins require light. Overcast days will lead to more yellows and browns.

Leaf Color Chemistry | Paper Chromatography with Autumn Leaves

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Why You Shouldn't Mix Bleach with Alcohol or Acetone

Mixing chemicals can be a bad idea, particularly if one of the chemicals is bleach. You may be aware household bleach gives off dangerous fumes when mixed with bases, such as ammonia, and acids, such as vinegar, but did you know it's also risky to mix it with alcohol? Bleach reacts with alcohol to form chloroform, a chemical that could knock you out and cause organ damage. Another chemical that reacts with bleach to form chloroform is acetone. While you wouldn't put bleach in a mixed drink, you might use it to clean up a spill or use it in a cleaning project with alcohol-containing glass cleaner. Acetone is found in pure form and in some nail polish removers. The bottom line: avoid mixing bleach with anything except water.

Image: Chemical structure of chloroform, CHCl3.

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