What is the largest diamond in the world? It turns out that this simple sounding question is slightly more complex. There are three different diamonds that vie for the title of largest cut diamond in the world, but each one of them is recognized for a different reason. The largest cut colorless diamond is called […]
#1797 What is the largest diamond in the world? Read More »
They failed for a combination of reasons. Some were overwhelmed by the enormous storm surge caused by Hurricane Katrina, while others failed because of weaknesses in their design and the soft soil supporting them. The flood defenses had also developed over many years rather than being designed as one integrated system. A levee is basically
#1788 Why did the levees in New Orleans fail? Read More »
What is a solar tube? A solar tube is a way of channeling natural sunlight into a house to provide natural illumination without needing power or a window. Solar tubes are also called light tubes, solar pipes, or sun tunnels. These names pretty much tell you exactly what they are designed to do. A lot
#1775 What is a solar tube? Read More »
Where do the expressions red herring, read the riot act, white elephant, and pay through the nose come from? A red herring is a clue that ends up not being relevant to the crime, or purposefully set to distract the police. The main theory of its origin is that it came from training dogs to
Will jumping just before an elevator crashes save you? Probably not. Even if someone managed to jump at the last second, they would still be moving downward at almost the same speed, so the change in the impact would be tiny. The real danger in a crash is not just “speed,” but how quickly that
#1764 Will jumping just before an elevator crashes save you? Read More »
Who invented the first eye chart? The first widely used eye chart was invented by a Dutch ophthalmologist called Herman Snellen. The earliest eye charts were invented in the early 19th century, but Snellen’s chart was the one that became the standard. The majority of people will have used an eye chart at some time.
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Why are leaves different shapes? Leaves are different shapes because of the conditions they have evolved to survive in. That might be for catching more sunlight, for saving water, to not be eaten by predators, or for staying cool. Leaves on a plant or a tree are a constant tradeoff. The main purpose of a
#1755 Why are leaves different shapes? Read More »
How can a bicycle freewheel? A bicycle can freewheel because of a ratchet and spring-loaded catches inside the gear hub. When you cycle on a bicycle, you use the pedals to apply energy to the chain, which transfers the energy to the wheels and makes you move forwards. You want that when you are on
#1739 How can a bicycle freewheel? Read More »
When did the modern census start? The modern census developed gradually between the late 17th and mid-19th centuries. Most civilizations have had some kind of census since the beginning of civilizations. It is always important to know how many people you have in your country because then you can tax them properly and you always
#1731 When did the modern census start? Read More »
How does the Netherlands reclaim land from the sea? They build a dike and then pump out the water. Before we look at how they do it, I thought it would be interesting to learn why Holland is called the Netherlands. Most of you probably know this, but I didn’t. The Netherlands is the official
#1727 How does the Netherlands reclaim land from the sea? Read More »
