Central Idea Practice

The First "Newspaper" War

The Crimean War was fought in the 1850s between Russia on one side and Britain, France, and Turkey on the other. Although it was a major conflict, it is perhaps best remembered as the first war in which journalists were present on the battlefield. News dispatches from William Howard Russell, a reporter for the Times of London, exposed military blunders and revealed the filthy conditions that existed in military hospitals and camps. Photographers such as James Robertson and Roger Fenton made hundreds of photographs of soldiers on the battlefield. These news reports and photographs provided an uncensored look at life on the front lines. The Crimean War marked the first time in history that people back home were exposed to the horrors of war.

What is the main idea of the passage?

• The Crimean War was the first war to be documented for civilians.

• The Crimean War was fought between the Russians and the British, French, and Turkish.

April Fools' Days Around the World

April Fools' Day is celebrated around the world, although it varies somewhat from country to country. In the United States, for example, it's a day to play practical jokes. In France, where the holiday is known as Poisson d'Avril, or April Fish, people secretly tape paper fish on their friends' backs. A common April Fools' prank in Portugal is to throw flour on someone; in Scotland, the most popular trick involves sending someone on a useless errand. Denmark celebrates April Fools' Day on April 1, but some people there celebrate again in May. Maj-kat, on May 1, is yet another day for jokes and pranks in the spring.

What is the main idea of the passage?

• On Poisson d'Avril, France's version of what Americans call April Fool's Day, pranksters tape paper fish to people's back.

• Though there are variations in how different countries observe April Fool's Day, the celebrations all involve playing pranks.

AC vs. DC

In the 1880s, the War of the Currents began. Thomas Edison developed direct current, or DC, a type of electricity that flows in one direction. By 1887, DC was in use around the United States. It had some drawbacks, though. Converting it to lower or higher voltages was difficult; that is, the current's force couldn't be changed easily. Transmitted at the low voltage needed for use in homes and businesses, it lost power after traveling only a mile. Meanwhile, Nikola Tesla was working with alternating current, or AC. AC reverses direction many times per second and can be changed to different voltages. At high voltage, it can be transmitted efficiently, traveling hundreds of miles with little energy loss. Because of its advantages, AC triumphed by the end of the nineteenth century.

What is the main idea of the passage?

• AC reverses direction and can be converted to lower or higher voltages.

• AC has distinct advantages over DC, so AC won the War of the Currents.

The Importance of Japan's Cherry Blossoms

In the northeastern United States, autumn is particularly colorful. Leaves change from green to red and orange, and many Americans take scenic fall foliage trips. In Japan, a similar phenomenon takes place in the spring. Cherry trees erupt in a shower of pink, and the entire country celebrates the arrival of sakura, or cherry blossoms. Though autumn leaves are admired in the United States, they are seen as just a pretty seasonal display. In Japan, on the other hand, cherry blossoms have much greater significance; the flowers are deeply rooted in Japan's culture and philosophy. Since as far back as the eighth century, sakura have symbolized change and beauty, new beginnings, and the circle of life. The blossoms have been celebrated in Japanese paintings, poems, and tea ceremonies for centuries.

What is the main idea of the passage?

• Japan's spring cherry blossoms often serve as symbols of change or new beginnings in works of Japanese art or literature.

• Americans appreciate the colorful leaves of fall, but the Japanese view the cherry blossoms of spring as part of their cultures.

Pay Inequality

In 2015, when the U.S. women's soccer team won its third World Cup title, the broadcast of the match had more viewers than any other soccer game in television history. Yet despite their prowess and fan support, the women's team makes as much as sixty-two percent less than the men's national team, according to a complaint filed by women players. The men's team earned $9 million for reaching only the sixteenth round of the 2014 World Cup. In contrast, the women received just $2 million for winning the 2015 title. In friendlies—games that don't count toward team rankings—the men were paid $5,000 dollars per game, plus a bonus of up to $17,625 for a victory. Women, on the other hand, earned just $3,600 per game with a $1,350 bonus for a win.

What is the main idea of the passage?

• In spite of their success and popularity, members of the U.S. Women's Soccer team are paid significantly less than their counterparts.

• The U.S. Women's Soccer team was paid only $2 million for winning the World Cup title in 2014.

The Evolving Human Skeleton

Our early ancestors were hunter-gatherers who obtained food by hunting and by searching for edible wild plants. They needed strong bones, including large, strong jaws that enabled them to eat tough, uncooked foods. When our ancestors developed agriculture, however, their diet changed. They began growing plants, such as grains and beans, and raising animals for food; they also started cooking their foods, making them softer and easier to chew. Consequently, the human skeleton underwent radical changes. Over time, the human jaw became smaller and changed shape. Other bones also evolved, becoming lighter, especially in the joints, as result of both dietary changes and a less active lifestyle.

What is the main idea of the passage?

• Early humans ate uncooked meats and vegetables, so they needed strong jaws for chewing.

• As early humans developed agriculture, their bones changed significantly.

Supporting Biliteracy

There are many good reasons to learn a second language. A second language can improve your understanding of your native language, open the door to new job opportunities, and help you learn about other cultures. Yet American students are less likely than European students to study foreign languages in school. To address this gap, several states have begun doing more to encourage biliteracy—the ability to read and write in two languages. California, New York, and Illinois are among the states that have passed laws establishing a state "Seal of Biliteracy." A Seal of Biliteracy shows that a student has achieved proficiency in a second language. Supporters of the seals say that they honor the importance of second-language learning. The seals also provide colleges and future employers with evidence of students' abilities.

What is the main idea of the passage?

• Fewer American students than European students learn a second language, so some states are promoting the study of foreign languages.

• Although second-language learning is important, students in the United States are less likely than those in Europe to learn a second language.

Eat Carrots, See Better?

Carrots contain high amounts of vitamin A and are good for general eye health. However, carrots will not improve night vision. That myth goes back to British propaganda during World War II. In 1940, the German Luftwaffe, or air force, began bombing Britain at night. In response, the British government ordered people to turn off their lights; the government wanted to make it difficult for German pilots to hit their targets. A new technology, radar, allowed the British air force to track and shoot down the German planes without light. To keep the technology secret, the government told the media that their pilots could see the German planes because they consumed so many carrots. Consequently, people began to believe that eating carrots would help them see better in the dark.

What is the main idea of the passage?

• During World War II, the British government told the media that their pilots ate a lot of carrots.

• Because of a British media campaign, people thought that eating carrots would improve their night vision.

Saving the Rhinos

Poachers in Africa are killing large numbers of rhinos for their horns. Rhinoceros horns, valued for use in traditional medicines in Vietnam and China, can fetch as much as thirty-six thousand dollars a pound. Officials have tried to protect the rhinos: they have created fenced areas for the animals, patrolled their habitats, and even tried removing their horns. Despite these efforts, the number of rhinos in Africa has been dwindling. One creative solution to the poaching problem is to remove the rhinos from Africa altogether. Ray Dear love, the founder of the Australian Rhino Project, came up with a plan to relocate eighty rhinos to a safari park outside Adelaide, Australia, where a breeding herd can be established.

What is the main idea of the passage?

• Because other attempts to protect African rhinos from poachers have failed, the Australian Rhino Project is relocating the rhinos to Australia.

• Officials have tried to protect African rhinos from poachers by guarding their habitats and removing their horns, but their efforts have been largely unsuccessful.

What's Beneath Your Plane?

As Shane Loeffler, a geology student at the University of Minnesota, was flying home from Europe, he looked down at the landscape and began to wonder what he was flying over. He realized that a plane flight would be a good opportunity for people to learn about the geological features of the earth below them. As a result of this experience, with a grant from the National Science Foundation, he created a free app called Flyover Country. The app provides users with information on natural formations, man-made features like dams, and even where fossils can be found. The features are pinpointed on a map that corresponds to the landscape below the plane.

What is the main idea of the passage?

• Shane Loeffler's plane flight home from Europe led him to think about the geological features of the land below him.

• Shane Loeffler's experience in a plane led him to create an app that would provide information to flyers about the land below them.