How did March 17 become St. Patrick’s Day?

When the time came to honour the patron saint of Ireland’s birthday, church officials gathered solemnly to choose a day, then realized that most of St. Patrick’s life was a mystery. They finally narrowed his birthdate down to either March 8 or 9, but because they couldn’t agree which was correct, they decided to add the two together and declared March 17 to be St. Patrick’s Day.

Why does my dog sometimes howl?

Like barking, growling, and whining, howling is one of the few forms of verbal communication that dogs have. Its roots go back to dogs’ wolf ancestry, when wild wolves used howling to communicate over long distances. The howl swept through different pitches, which helped the sound carry over longer distances. Wolves use howling to let other pack members know their precise location if they happen to get separated.

Other members of the pack howl back in reply—an acknowledgement that the sent message has been received. Wolves also howl to discourage a rival pack from encroaching on their territory. Dogs today still display some of this behavior. If you leave your house or apartment, your dog may howl to try to reestablish contact with you. If the howling persists after you’ve left, it could be a sign of separation anxiety. And sometimes dogs howl to establish their territory.

Why do we say that someone looking for trouble has a “chip on his shoulder”?

In early England, one man would challenge another to a duel by slapping his face with a glove. The challenge was a serious matter of honour, and if the slapped man did not accept it, he would be branded a coward. Having a chip on your shoulder was kind of an early Wild West equivalent of the glove slap, though generally less mortal in nature.

Boys and men would place a woodchip on their shoulder, challenging anyone who dared knock it off to a fistfight. So, if a man had a “chip on his shoulder,” he was clearly in an aggressive mood and spoiling for a fight.

What does it mean to “rest on your laurels”?

The practice of using laurels to symbolize victory came from the ancient Greeks. After winning on the battlefield, great warriors were crowned with a wreath of laurels, or bay leaves, to signify their supreme status during a victory parade.

Because the first Olympics consisted largely of war games, the champions were honoured in the same manner: with a laurel, a crown of leaves. To “rest on your laurels” means to quit while you’re ahead.

What is e-mail?

People can use the Internet to send electronic mail, known as e-mail, to one another in just a few seconds. Once you type a message into your computer to send to your cousin, let’s say, who lives miles from you across the country, it travels through the wires of your phone line as a series of electrical signals (or, for some people, the signals travel through the same cables that bring them cable television). These signals travel to a station run by your service provider, where a big computer sends them to an Internet routing center. Located all over the world, routing centers, which are linked to organizations and Internet providers, send the countless computer communications that come to them each second along the quickest possible routes to their destinations.

A giant computer there reads the address on your e-mail and sends it farther: depending on the distance it must travel, it may continue along phone lines, be changed into light signals that can travel with great speed along thin glass strands called fiber-optic cables, or be converted into equally speedy invisible bands of energy known as radio waves and transmitted to a communications satellite that will bounce it back to Earth, to a ground station located close to where your cousin lives. Once your message reaches the routing center nearest your cousin, it will be sent to the station of his or her service provider. From there it will be sent along regular phone lines to his or her computer. And all of this happens in a matter of moments.

Why do people get married?

Throughout the centuries—and in different parts of the world—men and women have married for a variety of reasons. It used to be common for young people to marry the person their parents chose for them, and some cultures continue to practice arranged marriages. Throughout most of the world today, however, a man and a woman usually marry because they love each other and want to be together and care for one another for the rest of their lives.

Adults often want to have children together and raise them in a family. While people don’t have to be married in order to have children, many people feel more comfortable raising a family as part of a married couple. When a man and a woman marry they make their permanent partnership public. After a marriage ceremony, they are connected by a legal contract— a marriage license—that can be dissolved by another legal decree known as a divorce (though death legally ends a marriage as well). Marriage grants a couple a new legal and social status, changing such things as the way they pay taxes and the amount they pay for health insurance.

What is an avalanche?

An avalanche is a huge mass of ice and snow that breaks away from the side of a mountain and slides downward at great speed. Most avalanches result from weather conditions, such as heavy winds and earth tremors, that cause snow on a mountain slope to become unstable.

A large avalanche in North America might release 300,000 cubic yards of snow—the equivalent of 20 football fields filled 10 feet (3.3 meters) deep with snow. Wintertime, particularly from December to April, is when most avalanches occur.

How did the dandelion and the daisy get their names?

The dandelion and the daisy are both named for a particular physical characteristic. The English daisy, with its small yellow centre and white- or rose-coloured rays, closes at night and reopens with daylight like the human eye, and so it was named the “day’s eye.”

The dandelion, because of its sharp, edible leaves, was named by the French “dent de lion,” the “tooth of a lion.”

Which was the smallest dinosaur?

The smallest dinosaurs were just slightly larger than a chicken. Compsognathus (meaning “pretty jaw”) was 3 feet (1 meter) long and probably weighed about 6.5 pounds (2.5 kilograms). At one time, scientists thought that Mussaurus (meaning “mouse lizard”) was the smallest dinosaur, but it is now known to be the hatchling of a dinosaur type that was much larger than Compsognathus when fully grown.

If birds are advanced dinosaurs, as some scientists believe, then the smallest dinosaur would be the hummingbird!

Why does a swimming pool appear less deep than is actually is?

The rays of light coming from the bottom of the pool pass from a denser medium (water) to a rarer medium (air) and are refracted (bend away from the normal).

When the rays return to the surface, they form an image of the bottom of the pool at a point, which is little above the real position.