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 […]
#315 How tall could a skyscraper be? Read More »
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 »
I learned this today. The British and American accents are different because the UK accents dropped a few things that the US kept. It is obviously difficult to generalize about UK and US accents because there are wildly different accents within each country. So, why do accents form? Accents form because of the history and
#245 Why are American and British accents different? Read More »
I learned this today. A spray bottle works by breaking the liquid up into tiny droplets using a pump and different kinds of nozzles. Modern spray bottles work slightly differently to older spray bottles. The first kind of spray bottles used a rubber bulb and an atomizer nozzle. They were invented by an American called
#242 How does a spray bottle work? Read More »
I learned this today. The Sahara Desert has grown so big because the precession of the Earth’s axis as it rotates around the sun changes the location of the African monsoon. The Sahara Desert is 9.2 million square kilometers, which makes it bigger than every country except for Russia, Canada, China and the USA. The
#229 How did the Sahara Desert get so big? Read More »
