The stone test wall, more than 12 feet high and 37 feet long, is made up of 2,352 stone samples. The wall was originally constructed in 1948 at the NBS site in Washington, D.C. It was moved to its present location in 1977.
By the mid-1980s, some samples, especially sandstones, were beginning to crumble, crack, or flake away. Many limestones developed a surface texture showing fossil fragments.
Curiously named neighborhood restaurant in Toronto.
This restaurant, at 516 Eglinton Avenue West, is one of two branches, both named 7 Numbers, but one is 2113407 and other is 2047409. Each number happens to be the seven-digit Ontario corporation number issued by the Ministry of Government Services to any business paying taxes in the province.
2113407 = 3 x 3 x 43 x 43 x 127.
It happens to have two factors in common with its address number: 516 = 2 x 2 x 3 x 43.
Eastern Orthodox churches often have a set of three bells outside the main building, which play a role in various traditional religious practices. The three bells shown, each one a different size to produce a different tone, are at Vardzia, a cave monastery site in southern Georgia.
The installation consisted of 300 incandescent light bulbs arranged in a spiral paraboloid.
Sensor handles beneath the towering array of light bulbs detected a user's heartbeat, and software translated this signal into rhythmic flashes, with signals from successive users moving up the spiral.
Temari is a folk art form that originated in China and was later introduced to Japan. A Temari ball is constructed from a spherical core wrapped in yarn, then decorated with colored threads to create geometrical patterns on its surface.
Artist and inventor Kenneth Snelson has proposed his own model of the atom. This eight-magnet example is one of a series of small geometric figures, dubbed magnet circlespheres, made up of equal-diameter magnets to illustrate his concept of an atom's electronic structure. When one magnet is turned by hand, the rest follow like a circular chain of gears.
In Gustave Eiffel's innovative design, a central pylon with a secondary framework reaches out to the Statue of Liberty's copper skin.
The copper sheets are attached to iron ribs in such a way that the skin is still free to shift slightly. Because of corrosion, the original ribs had to be replaced during the 1984-86 restoration of the Statue of Liberty with new stainless steel bars that were shaped to match the contours of the old bars.
The lighting scheme created for the refurbished Statue of Liberty was designed to capture the quality of natural daylight. In 2015, an LED-based lighting system was introduced.
The Statue of Liberty's original torch and flame, now on display in the Liberty Island museum, had to be replaced during the restoration because of extensive corrosion damage. Holes cut into the copper flame allowed moisture to leak into the statue's arm.
Constructed about 4,000 years ago on Salisbury Plain in southern England, Stonehenge stands as an astronomical monument. Alignments of various stones point to locations where the sun and moon rise at key times throughout the year.
The central avenue of Stonehenge points to the northernmost rising of the sun. At the summer solstice, observers can see the rising sun dramatically skim a large outlying marker known as the Heel Stone, framed by the monument's ancient pillars.
Welcome to an occasional series devoted to "cool stuff" that I encounter while browsing the world of mathematics and computer science. I'll peek at new developments in math and its applications, and I'll revisit old puzzles, famous problems, and historic events—anything mathematical that happens to catch my eye. I hope you'll find something of value in these brief, informal forays into the world of math.
Ivars Peterson is a freelance writer and editor. He was Director of Publications at the Mathematical Association of America from 2007 to 2014. As an award-winning mathematics writer, he previously worked at Science News for more than 25 years and served as editor of Science News Online and Science News for Kids. His books include The Mathematical Tourist, Islands of Truth, Newton's Clock, and Fragments of Infinity: A Kaleidoscope of Math and Art.