Why do we say boycott? The word comes from a British land agent who lived in Ireland. His name was Captain Charles Cunningham Boycott. He was born in England in 1832. He joined the army when his family paid for his commission in 1850. He was not able to join on the strength of his […]
#339 Why do we say boycott? Read More »
What is the opposite of white? Either black or transparent. Let’s look at what colors are, what white is, and what black and transparent are. Colors appear when an object reflects a certain wavelength of light. Light is energy that is flying through space, called electromagnetic radiation. There are many different types of light and
#331 What is the opposite of white? Read More »
How does crop rotation work? By alternating crops to give the soil a rest and to replace nutrients that are removed. People transitioned from a hunter-gatherer culture to an agricultural culture in about 12000 BC. First, they domesticated animals. This happened in different places on Earth within a few thousand years. In about 9500 BC,
#317 How does crop rotation work? Read More »
How tall could a skyscraper be? Theoretically 69.1 km tall, but practically, about 2 km. The tallest building in the world at the moment is the Burj Khalifa. It is 830 meters tall. For over 3800 years, the tallest building in the world was the Great Pyramid at Giza. It was 147 meters tall when
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How does a photocopier work? They work because light carries energy and opposite electric charges attract. The first principle that the photocopier relies on is that light carries energy. Light is a little difficult to understand. According to Einstein, anything that travels at the speed of light cannot have any mass. If something has mass
#299 How does a photocopier work? Read More »
When did people start using punctuation? The Greeks were the first people to use punctuation, but the Bible made it commonplace. Most early languages used a writing system that was based on images. There was no need for punctuation or even spaces because the ideas were contained in the symbols. Modern languages like Japanese and
#295 When did people start using punctuation? Read More »
How do you build a tunnel underwater? You can either build the tunnel above ground in pieces and lower it into the water, or you can dig the tunnel underground. Humans have been making tunnels for thousands of years. The art of tunneling probably started when prehistoric people wanted to make their caves bigger.
#287 How do you build a tunnel underwater? Read More »
I learned this today. Scaffolding is attached to the building by placing ties through windows, by drilling holes in the brick, or by anchoring them to the ground. Scaffolding has been used for thousands of years. Sockets have been found in the walls around the cave paintings in the Lascaux cave network. These paintings are
#274 How is scaffolding attached to a building? Read More »
I learned this today. A hand grenade works because the removal of the lever starts a series of steps that ends with an explosion. There are many different types of grenade. I am going to look at the fragmentation grenade. Most of us imagine the Mk 2 grenade when we think of a hand grenade.
#259 How does a hand grenade work? Read More »
I learned this today. The Richter scale is a way of measuring the strength of an earthquake by looking at the height of its seismic wave. The Richter scale was developed in 1935 by Charles Francis Richter. He was an American physicist who was very interested in seismology. He came up with his system because
#256 What is the Richter scale? Read More »
