At first glance, it’s hard to tell a porpoise and a dolphin apart from one another. Both are fascinating undersea creatures, both are carnivores, and both belong to the same scientific group: Cetacea. However, there are slight physical differences between the two: Porpoises tend to be smaller than dolphins and do not have pronounced beaks. Dolphins have cone-shaped teeth, while porpoises have spadeshaped teeth. Dolphins usually have a hooked or curved dorsal fin, and porpoises usually have a triangle-shaped dorsal fin. (Some have no dorsal fin at all.) There are over 30 species of true dolphins, including familiar species like the bottlenose, spinner, and spotted dolphins.
Walking with your dog strengthens the bond between you and your pet, and it is also the healthy thing to do. Dogs, like people, benefit from exercise to help control weight and to maintain a healthy heart, lungs, and muscles. They love going for a walk, running and jumping, and retrieving a ball or Frisbee. Aging pets must be kept as agile and fit as possible, but may not be motivated to exercise without encouragement. The pleasure of your company is one of your dog’s greatest motivations to exercise.
In addition to exercise, dogs also need social interaction, positive attention from their owner, and mental stimulation. Many of these needs can be met by simply taking your dog for a walk. Always remember to walk your dog on a secure leash (with identification tags) and pick up after your pet. During warm weather carry water for your pet, and always pause when your dog needs a rest.
Indeed, it does. A Venus flytrap is a carnivorous plant that attracts, captures, and kills insects and digests and absorbs their nutrients. The leaves of the Venus flytrap, Which can open wide, have short, stiff hairs called trigger hairs. When anything touches these hairs enough to bend them, the two lobes of the leaves snap shut, trapping whatever is inside. The “trap” will shut in less than a second, capturing flies and other insects.
When the trap closes over its prey, finger-like projections called cilia keep larger insects inside. In a few minutes the trap shuts tightly and forms an air-tight seal in order to keep its digestive fluids inside. These fluids help the plant digest prey. At the end of the digestive process, which takes from 5 to 12 days, the trap reabsorbs the digestive fluid and reopens. The leftover parts of the insect blow away in the wind or are washed away by rain.
Paint coats wood, protecting it from sunlight and rain damage and making it last longer. When early farmers had enough money to paint their barns, they usually used inexpensive paint because the structures were so large. Ferrous oxide, a chemical powder that gives paint its red color, was readily available and cost little. Thrifty farmers in New England, New York, and the upper Midwest region painted their barns red. In those places, red barns remain a tradition. But there are plenty of barns in other parts of the country that are not red. Early farmers that were poor—especially in regions like Appalachia and the South—left their barns unpainted because they did not have the money to do the job.
Unpainted wood usually weathers to a soft gray color. And in places like Pennsylvania, Maryland, and some southern Midwestern states, the most frequently seen barn color is white. Some people think that white barns grew popular when dairy farming became more important after the Civil War; white suggests cleanliness and purity, desirable qualities to be associated with milk production. Special farms where fancy horses or prize livestock were raised sometimes had barns painted unusual colors, like yellow, green, or black.
Because two eyes do not form exactly similar images and he fusion of these two dissimilar images in the brain gives three dimensions of the stereoscopic vision.
The expression dates back to the English Crown’s first efforts to control the Irish by outlawing their language and customs. But the unruly Irish were just that, and by the fifteenth century the English still controlled only a small area around Dublin, protected by a fortification called “The Pale,” meaning sharp sticks (i.e., impaled). To the British, to go “beyond The Pale” meant that you were entering the uncivilized realm of the wild Irish.
Schools are different in every country in the world. A school may have lots of classrooms, books, play equipment, and a playground, or lessons may take place under trees or in an open outdoor space. A temple, a tent, or a building on stilts may serve as a classroom for some children. In poor places that have no money to build schools, children may learn their lessons outdoors. In isolated places—such as the Australian outback or the Alaskan wilderness—where families live hundreds of miles apart and far from cities or towns, children may get their lessons from teachers over two-way radios or the Internet. All around the world, schools are a reflection of the culture in which they are formed.
In Japan, as students enter school, they remove their shoes and put on slippers, a Japanese custom. They do not write with pencils; instead, each child has his or her own ink well, brush, and ink for writing the kanji (Japanese characters). Children often clean their classrooms (including dusting cubbies and mopping floors), and at the end of each class the students thank their teacher and bow. In schools in Brazil and other South American countries, children often go to school barefoot. In India, children practice yoga in school. And many children that go to public schools in European countries, such as Germany and France, ride their bikes to school or take public transportation, rather than school buses.
Pen pals (also called pen friends) are people who regularly write to each other, particularly via postal mail. They are often located in faraway places, such as other states and countries. A pen pal relationship is often used to practice reading and writing in a foreign language, to improve literacy, to learn more about other countries and lifestyles, and to feel connected to people in other parts of the world which helps the world feel like a much smaller place! Pen pals come in all ages, nationalities, and cultures.
Pals may seek new pals based on their own age group or a shared common interest, such as a specific sport or hobby, or they may select someone totally different to gain knowledge about a foreign culture (such as the Far East, Europe, or South America). With the advent of the Internet, a modern version on the traditional pen pal arrangement has developed, and many pen pals also exchange e-mail addresses as well as, or instead of, paper letters. In order to connect with a pen pal, get your mom or dad’s permission first. Often, online sites dedicated to pen pal communication can help you connect with a student your own age.
Early in human history, people used anything that they could find to keep their teeth clean. Usually a thin, sharp object, like a stick, was used to pick out food left between teeth. Chewing on the end of certain sticks would fray the wood, making a kind of brush, which could then be rubbed across the teeth. (Even today, members of primitive tribes chew sticks to keep their teeth clean. The constant chewing produces more saliva than usual, which helps wash food away.) Later, people found that if they rubbed abrasive elements, like salt or chalk, across their teeth, they could get rid of grime. They also used water and pieces of rough cloth to clean their teeth. Toothpicks made of all kinds of materials also became popular. Rich people had jeweled toothpicks made of gold and silver. Toothbrushes for the wealthy, with fancy handles and hog bristles, came into use in the eighteenth century.
Only much later, when cheaper, woodenhandled toothbrushes were made, and the importance of good dental hygiene became known, did most people start to regularly use them.
Earrings were used by seamen, especially warriors such as pirates, for very practical reasons and not for decoration. They were given to young sailors as a symbol of their first crossing of the equator, and their purpose was to protect the eardrums during battle.
The pirates, especially those who fired the ships’ cannons during closed combat with the enemy, dangled wads of wax from their earrings to use as earplugs.