What is the Roche limit? The Roche limit is the minimum distance that one planetary body can approach another planetary body without being torn to pieces. The Roche limit is named after Edouard Roche, the French astronomer who first calculated it in 1848. He came up with his theory while he was studying the rings […]
#1526 What is the Roche limit? Read More »
Why was the Erie Canal important? The Erie Canal was important because it connected the Atlantic Ocean to the Great Lakes. This cut down shipping time and costs, and it unlocked the American Midwest. The Erie Canal is 584 km long. It runs from the Hudson River in New York State to Lake Erie. The
#1525 Why was the Erie Canal important? Read More »
When did castles stop using moats? Castles stopped using moats in the 16th century, and the whole design of castles changed to reflect new technology in warfare. If you have ever visited the ruins of an old castle, you probably noticed that you need to cross a bridge to get into it. The bridge spans
#1724 When did castles stop using moats? Read More »
What is a magnetar? A magnetar is a neutron star that is the size of a city but is one of the strongest magnetic objects in the universe. Many planets and stars have a magnetic field. Our Earth has a magnetic field that is produced by the spinning liquid metal in the outer core. The
#1723 What is a magnetar? Read More »
Why don’t spiders get stuck in their own webs? Spiders don’t get stuck because not all of the web is sticky, they know where to put their feet, and their feet are adapted for walking on silk. There may also be chemical help from their legs, but that part is still not completely proven. Spiders
#1722 Why don’t spiders get stuck in their own webs? Read More »
Why doesn’t the US control the Panama Canal anymore? The US doesn’t control the Panama Canal at the moment. It is owned and operated by the country of Panama. The US owned it until 1999. The Panama Canal is an 82 km long waterway that cuts through the narrowest part of Panama and connects the
#1721 Why doesn’t the US control the Panama Canal anymore? Read More »
How did a gardener build the Crystal Palace? Joseph Paxton was head gardener for William Cavendish, 6th Duke of Devonshire, and an expert in greenhouses and large glass structures. When all other designs for the Crystal Palace were rejected, he submitted his own, which was chosen. The Crystal Palace was an enormous cast-iron and plate
#1720 How did a gardener build the Crystal Palace? Read More »
What causes a drought? At its simplest, a drought happens when an area has less water than it normally needs, often because of a lack of precipitation. Some droughts are meteorological, meaning there is not enough rain. Some are agricultural, meaning the soil is too dry for crops. Some are hydrological, meaning rivers, lakes, reservoirs,
#1719 What causes a drought? Read More »
What was the Zimmerman telegram? The Zimmerman telegram was the device the US used as an excuse to join World War 1. World War 1 started in 1914 and lasted until November of 1918. The German forces moved quickly, but very soon, both sides were bogged down in trenches and it became a war of
#1718 What was the Zimmerman telegram? Read More »
Why do some animals live in groups and others don’t? Prey animals that live in groups tend to do so for safety. Predators that live in groups tend to do so because it makes them better hunters. Some animals might also live in groups to keep warm, or because it makes it easier to find
#1717 Why do some animals live in groups and others don’t? Read More »
