Why does coral bleaching occur? Coral bleaching primarily occurs because heat stress causes the coral to expel the algae that give them their beautiful colors. If you go diving in a tropical region, you will probably see enormous numbers of coral. They should be a whole range of beautiful colors, but these days, enormous numbers […]
#1498 Why does coral bleaching occur? Read More »
How does a watch keep time? Modern watches use a quartz movement to keep time, but mechanical watches use a wound spring. Modern watches are probably easier to understand, so let’s look at those first. They work on the principle of piezoelectricity, which is a property that the mineral quartz possesses. The piezoelectric effect is
#1497 How does a watch keep time? Read More »
How does an airplane de-icing system work? The plane’s wings are sprayed with a heated, high-pressure solution of propylene glycol and water. Planes fly throughout the year, in all kinds of weather, and there is very little that can stop them. When they fly, they have to avoid heavy storms, but rain is generally not
#1496 How does an airplane de-icing system work? Read More »
What is the honeybee waggle dance? Honeybees do a waggle dance to communicate the distance and the direction away from the hive of a patch of flowers. It demonstrates that bees can remember information, communicate that information, and that other bees can understand it. It is a fairly complex type of communication. When you think
#1495 What is the honeybee waggle dance? Read More »
What is a Stirling engine? A Stirling engine is an engine that uses the expansion and contraction of a gas when heated and cooled to carry out mechanical work. A Stirling engine works on the principle that gases expand when heated and contract when cooled. When thermal energy is applied to a gas, the molecules
#1494 What is a Stirling engine? Read More »
What causes a hangover? A hangover is caused by a combination of things, including acetaldehyde poisoning, dehydration, inflammation, irritation of the stomach, low blood sugar, and lack of sleep. As an interesting aside, the word “hangover” only became associated with the morning after drinking too much in 1904. It was used in the Foolish Dictionary,
#1493 What causes a hangover? Read More »
How much air does a hovercraft need? The amount of air a hovercraft needs obviously depends on its weight, its size, the speed of its fans, and the quality of the skirt around it. Hovercraft work by producing pressurized air underneath them, which lifts the hovercraft off the ground. A second fan at the back
#1492 How much air does a hovercraft need? Read More »
How does a fountain pen work? A fountain pen works because of gravity, surface tension, and capillary action. The fountain pen essentially has three parts. At the back, underneath the part you hold, is the ink reservoir. This is usually a disposable cartridge, but it can be a refillable one. The cartridges are sealed until
#1491 How does a fountain pen work? Read More »
What is the Kessler syndrome? The Kessler syndrome is a situation where there is so much space debris in low Earth orbit that pieces start to collide, breaking them into smaller pieces, and causing the collisions to increase. The Kessler syndrome was named after a study written by Donald Kessler and Burton Cour-Palais in 1978
#1490 What is the Kessler syndrome? Read More »
Was there an intelligent civilization on Earth before us? There almost certainly was not an intelligent civilization on Earth before us. They would have left signs that could not be mistaken. The thought that an ancient civilization might have existed on Earth is called the Silurian hypothesis, named after such a species that exist in
#1489 Was there an intelligent civilization on Earth before us? Read More »
