Why do baby boys wear blue and girls wear pink?

The custom of dressing baby boys in blue clothes began around 1400. Blue was the colour of the sky and therefore Heaven, so it was believed that the colour warded off evil spirits. Male children were considered a greater blessing than females, so it was assumed that demons had no interest in girls.

It was another hundred years before girls were given red as a colour, which was later softened to pink.

Why do we call the perfect world “Utopia”?

The word Utopia was created by the English philosopher Sir Thomas More in 1516 and was the title of his book that compared the state of life in Europe at the time with an imaginary ideal society. Utopia is from Greek meaning nowhere.

The thrust of More’s message was that an ideal world, or Utopia, will never exist, and that our only choice is to improve the standards of our existing society.

Is it true that parts of Earth are always covered in ice?

About one-tenth of Earth’s surface is always under the cover of ice. And almost 90 percent of that ice is found in the continent of Antarctica. The remaining 10 percent is found on the mountains in the form of glaciers.

The ice sheet that covers Antarctica is almost one-and-a-half times the size of the United States.

What do potato chips have to do with the heart?

Potato chips often contain saturated fats, which over time can clog the arteries that carry blood to the heart. The oils used to cook the chips are made up of saturated fats, which increases cholesterol production in the body, a known risk factor for heart disease.

Heart disease results from a condition known as atherosclerosis, which happens when a waxy substance forms inside the arteries that supply blood to your heart.

How does the metal switch in a toaster bend?

It bends because it is made of two metals that are joined together, something called a bimetal switch. One metal (usually brass) expands quickly when heated, while the other expands much more slowly. This difference causes the switch to bend toward the low-expansion metal.

Bimetal switches are used in other appliances that switch electricity on and off to keep their temperatures even, like irons and refrigerators. The thermostat that regulates the temperature of your home by turning your furnace and air conditioner on and off also uses a bimetal switch.

Can farm animals be cloned?

Yes. In 1997 a team of scientists at the Roslin Institute in Edinburgh, Scotland, announced the birth of Dolly the sheep, the first clone (identical copy) of an adult mammal. The process used to create Dolly, called somatic cell nuclear transfer, began with an egg cell from one sheep. The scientists destroyed that egg cell’s nucleus and then injected the nucleus from the cell of another sheep into the egg cell. With a little encouragement from electronic stimulation, the donated nucleus fused with the egg cell, and the new cell began to divide.

The cluster of cells was then implanted into the uterus of the sheep that had provided the egg cell, and five months later Dolly was born—an exact replica not of the sheep that had carried her in the womb but of the sheep that had supplied the nucleus. While cloning mammals is very controversial, some scientists argue that cloning farm animals has advantages to livestock farmers, who could use the technology to breed only highquality animals that produce the most milk or the finest wool.

Why does a lizard need to lie in the sunshine to get energy?

The lizard is a reptile, a cold-blooded animal that is unable to internally control its own body temperature. In order to warm up or cool down, lizards and other reptiles—such as snakes, turtles, and crocodiles—move to different areas of their environment. They also use certain other behavioral traits to keep their body temperatures constant. For instance, if a lizard is starting to feel the intensity of the tropical sun, it might head into the shade or take a dip in a pool of water. The same lizard might also bask in the sun to warm up. Frilled dragons and collared lizards run on their hind legs in the heat of the day, making an artificial breeze to help cool themselves off. And another reptile, the crocodile, holds its jaws open to cool down on hot days.

The blood vessels in its mouth are close to the skin surface, and help transfer heat. Lying quietly is another technique the crocodile uses to warm its body and help digest its food. Because they are cold-blooded, reptiles can survive on much less food, compared to warm-blooded small mammals and birds, which burn much of their food to keep warm.

Which religions are the most widely practiced around the world?

Today there are some 4,300 religions in the world. Nearly 75 percent of the world’s population practices one of the five most influential religions of the world: Christianity, Buddhism, Hinduism, Islam, and Judaism. Christianity, which is based on the teachings of Jesus Christ, who preached in Palestine about 2,000 years ago, is the most widely practiced religion in the world today, with 2.1 billion followers.

The second most practiced religion is Islam, with 1.3 billion followers.

What do I do if I am being bullied?

Lots of kids have been picked on by a bully, for many different reasons. Bullying is intentional tormenting in physical, verbal, or psychological ways, and can range from hitting, shoving, name-calling, threats, and mocking to taking lunch money or personal items. If you’ve been the target of a bully, you know it can be very scary and upsetting to be teased, hit, or threatened.

Sometimes it helps to simply ignore what the bully is saying—most bullies tease or threaten other kids to get a reaction from those they tease, and if they get no reaction at all, it’s a lot less fun for them. It usually helps to have friends around. A kid walking alone is more vulnerable than a group of kids. And even if you don’t feel confident, sometimes acting confident helps. If you hold your head high and tell a bully to stop calling you names, you may just surprise that bully into silence. One approach to avoid is responding to bullying with fighting or bullying back—aggressive responses will only make matters worse.

What is the International Date Line?

Located at 0 degrees longitude, the prime meridian passes through Greenwich, England. Halfway around the world in the middle of the Pacific Ocean (180 degrees from Greenwich) is the International Date Line (IDL), where the date changes across the boundary of the time zone.

The entire world is on the same date only at the instant when it is noon in Greenwich, England, and midnight at the IDL. At all other times, there are different dates on each side of the IDL.