Top 10 technology factsTechnology quiz
Why were photographic prints sepia toned?
For improved resistance. Sepia toning enhances archival qualities of the photos. Chemicals are used to convert the metallic silver in the print to a sulfide compound, which is at least 50% more stable than silver.
What was the maximum effective range of the Paris Gun?
130 km. The Paris Gun was a German long-range siege gun used to bombard Paris during World War I. The gun was capable of firing a 94 kilogram (210 lb) shell to a maximum altitude of 40 kilometers (25 miles, 131,000 ft). It was the first time for human-made object to reach stratosphere.
The Santísima Trinidad (pictured) bore the most guns of any ship of the line outfitted in the Age of Sail. How many guns were there?
140. Santísima Trinidad was one of few four-deckers ever built. The weight of the additional guns, so high above her waterline, made her sail poorly, leading to her nickname, El Ponderoso. She sank after the Battle of Trafalgar, where her great size made her a first target for the British fleet, and she came under concentrated attack by several ships.
What is larger in the sky: the Moon or the Sun? (By apparent size)
Sometimes the Moon, sometimes the Sun. The Moon's orbit is elliptical, and its apparent diameter varies by 10%. This is why both total eclipses (if the Moon is larger) and annular eclipses (if the Sun is larger) happen.
At what temperature does water boil at the top of Mt Everest?
68°C (154.4°F). The boiling point of water depends on the pressure. On top of Mount Everest, the pressure is about 260 mbar (26.39 kPa) and the boiling point of water is 69 °C. (156.2 °F). In contrast, water can still remain liquid near deep hydrothermal vents, even if the temperature is very high.
What is the only physical difference between heavy water and pure water?
Heavy water has greater density. Heavy water contains deuterium instead of common hydrogen-1. In its pure form it has a density about 11% greater than water, but otherwise, it is physically and chemically similar. It is not radioactive. Because of greater density and stronger hydrogen-oxygen bonds, its behaviour is slightly different in some biochemical reactions. It may be toxic, but only when a large fraction of water (> 50%) in higher organisms is replaced by heavy water.
Which numeral system was in use in ancient Sumer and Babylon?
Sexagesimal. Remnants of the highly composite sexagesimal system are in use even today for time measurement and geometry. An hour of time is divided into 60 minutes, which in turn are divided into 60 seconds.
HMS Victory is the only surviving example of a ship of the line. Where does the name "of the line" come from?
She could be used to form a line of battle. The line of battle was a naval tactic in which ships form a line, so each ship can fire its broadside without fear of hitting a friendly ship. As breaking of the line ruined this tactic, only the powerful ships (called "ship of the line") were used.
Maria Skłodowska-Curie was committed to her job. Did she have any children?
Her daughter was awarded the Nobel Prize. Her first daughter, Irene, decided to follow her mother's life path and received the Nobel Prize in chemistry in 1935. Her second daughter, Eva, a writer and politician, was known as the "First Lady of UNICEF". She was also nominated for the Pulitzer Prize in 1944.
The closest star to the Sun is Proxima Centauri. In which direction we would need to look to see it in the night sky?
It is not visible at all. Proxima Centauri is a red dwarf and its average brightness is very low. That is why even though it is closest to the Sun, it was discovered not until in 1915.