Main Idea Practice

The Marines had a problem in World War II. Orders were sent in code, but the enemy kept learning the code. Nothing could be kept secret. Then someone thought the Navajo soldiers could help the Marines. Since very few other people could speak Navajo, this language was used as a code. No one on the enemy side knew Navajo, so the messages stayed secret.

• How Navajo people kept secrets.

• When the secret code was used.

• How the Marines used Navajo as a code.

• Why the original code had to be changed.

Answer explanation

Marine Corps leadership selected 29 Navajo men, the Navajo Code Talkers, who created a code based on the complex, unwritten Navajo language. The code primarily used word association by assigning a Navajo word to key phrases and military tactics.

Tags

CCSS.RI.6.2

CCSS.RI.8.2

CCSS.RL.6.2

CCSS.RL.7.2

CCSS.RL.8.2

Bob Geldof talked to the top musical talents of the world and asked them to sing at a concert to raise money. The stars agreed. Geldof found a stadium, arranged for TV coverage, and set up a trust fund. He said that none of the stars would get special treatment. Everyone would work together. In 1985, the Live Aid concert raised more than $100 million for starving children.

• How Geldof found a stadium.

• How many musical stars agreed to sing.

• Why world hunger is a problem.

• How a concert benefitted starving children.

Answer explanation

Bob Geldof of The Boomtown Rats had one hit song called, "I Don't Like Mondays." The 1985 Live Aid concert, held simultaneously in London and Philadelphia, raised over $127 million dollars to feed children.

Tags

CCSS.RI.5.5

CCSS.RI.6.5

CCSS.RI.7.5

CCSS.RI.8.5

CCSS.RI.9-10.5

For years food chemists have tasted hot peppers used for chili sauce, ketchup, and pizza, but people had a hard time figuring out the spiciness of the peppers. After eating two or three, their taste buds were burning. Now a machine can test different kinds of hot peppers. It measures the chemicals that provide the spicy taste of the peppers.

• How scientists measure chemicals.

• How hot and spicy peppers are used.

• Why people have trouble tasting hot peppers.

• How a machine helps the hot pepper industry.

Answer explanation

Scoville heat units, also known as SHU is simply a measurement of the number of times capsaicin needs to be diluted by sugar-water. The number of Scoville Heat Units (SHU) in a pepper or even hot sauce indicates the amount of capsaicin present. The higher the Scoville rating, the hotter the pepper.

Tags

CCSS.RI.6.2

CCSS.RI.7.2

CCSS.RI.8.2

CCSS.RL.7.2

CCSS.RL.8.2

Sharks have a keen sense of hearing and can smell blood from almost 2,000 yards away. Sharks also have a special system of channels in their skin that helps them feel the vibrations of a splashing swimmer. We know that in clear water, sharks can see dinner from about 50 feet away. If you ever spot a shark, always swim away smoothly!

• How well sharks hear.

• Why sharks have poor vision.

• How sharks sense food.

• When to swim away smoothly.

Answer explanation

Sharks have several extraordinary senses that help them find prey.

Usually, they use their ampullae of Lorenzini and electricity detection sense to find prey from long distances. As they get closer to you, their smelling, hearing, and visual capabilities are essential to verify that the prey is edible.

Tags

CCSS.RI.7.2

CCSS.RI.8.2

CCSS.RL.6.2

CCSS.RL.7.2

CCSS.RL.8.2

 "The War of the Worlds" was a radio story which started a panic in 1938. Because many people didn't hear that it was just a story about monsters from space, they thought the fake news bulletins were real. People were frantic, thinking they were under attack by aliens. It took hours to calm them down and convince them that it was only a radio play.

• How a radio play fooled many people.

• What people thought about news stories.

• Why people were afraid of the monsters.

• Where the monsters in the story came from.

Answer explanation

A radio play of H.G. Wells’s The War of the Worlds had fake news bulletins of a Martian invasion of New Jersey. Some listeners mistook it for the real thing, calling police, newspapers, and radio stations. By the next morning, Orson Welles’s face was on the front pages of newspapers coast-to-coast.

Tags

CCSS.RI.6.2

CCSS.RI.8.2

CCSS.RL.6.2

CCSS.RL.7.2

CCSS.RL.8.2

Some college teachers in Michigan have made a small computer that looks like an orange. It will be picked and handled like real fruit. Since much fruit is damaged on its way to market, this machine will measure shaking and temperature changes. The computerized orange will help people find ways to avoid damaging fruits during shipping.

• When the computerized orange was created.

• How the computer company helped make the machine.

• What the computerized orange looks like.

• About the purpose of the computerized orange.

Answer explanation

The logistics of transporting fresh produce is very complex, and members of the supply chain must work together so that the produce can make it to customers in perfect condition. They must take into account packaging, temperature, humidity, and other factors to ensure the produce stays fresh and intact.

Tags

CCSS.RI.6.2

CCSS.RI.7.2

CCSS.RI.8.2

CCSS.RL.6.2

CCSS.RL.7.2

Because lambs are sometimes eaten by coyotes, ranchers may hunt or trap the coyotes. However, killing coyotes may upset nature's balance. Scientists have found a way to protect sheep without killing coyotes. Coyotes are fed lamb meat treated with a drug. When they eat the meat, they get sick. Later, coyotes won't even go near lambs. They'll hunt rabbits instead.

• Why coyotes prefer rabbits to lambs.

• Why killing coyotes upsets nature's balance.

• How scientists protect sheep and coyotes.

• What kind of people don't like coyotes.

Answer explanation

After conditioned taste-aversion treatment, coyotes did not catch and eat live lambs. After one or two meals of lamb meat containing lithium chloride (which causes gastrointestinal discomfort), six coyotes did not attack lambs.

Tags

CCSS.RI.6.2

CCSS.RI.7.2

CCSS.RI.8.2

CCSS.RL.7.2

CCSS.RL.8.2

In real life, rattlesnakes try to avoid people and seldom attack. Most people are bitten only after they step on these snakes. A rattlesnake may not even inject its poison when it bites. In fact, more Americans die from insect stings than from snakebites!

• How rattlesnakes are not as dangerous as everyone belives.

• Why insects kill people.

• When rattlesnakes use their poison.

• How snakes bite.

Answer explanation

Rattlesnakes Are Not as Dangerous as Ladders, Trees, Dogs, or Large TVs. Bugs and food poisoning actually kill many more people than rattlesnakes do.

Tags

CCSS.RI.7.2

CCSS.RI.8.2

CCSS.RL.6.2

CCSS.RL.7.2

CCSS.RL.8.2

Alfred Nobel invented dynamite to help builders, but it was used for war, which made him feel very guilty about the misuse of his invention. He was a rich man, so he set up a $9 million fund. Today the fund is used to reward people who have improved human life. Nobel Prizes are awarded in six fields, including peace, medicine, and chemistry.

• What Nobel Prizes are awarded for.

• Why Nobel founded the Nobel Prize Fund.

• How much money was set aside for awards.

• What invention Alfred Nobel created.

Answer explanation

In 1888, the death of his brother Ludvig caused newspapers to publish obituaries of Alfred in error. Nobel read this and was appalled that he would be remembered in this way. His decision to donate the majority of his wealth to found the Nobel Prize has been credited to him wanting to leave a better legacy.

Tags

CCSS.RI.6.2

CCSS.RI.7.2

CCSS.RL.6.2

CCSS.RL.7.2

CCSS.RL.8.2

The lack of gravity in space makes even simple tasks a challenge. Astronauts have to wear boots that hold their feet to the floor so that they can walk around. Eating is a real chore. Dried and frozen foods are stored in plastic bags. To eat chicken soup, the astronauts cut a hole in one end of the bag and squeeze the soup into their mouths.

• Why there is little gravity in space.

• Why easy tasks are challenging in space.

• Why space food in stored in plastic bags.

• How to eat chicken soup.

Answer explanation

There are no refrigerators in space, so food must be stored and prepared properly to avoid spoilage. Salt and pepper are available only in liquid form because astronauts can't sprinkle salt and pepper on their food. The salt and pepper would float away. clog vents, contaminate equipment or get stuck in an astronaut's eyes or nose.

Tags

CCSS.RI.4.5

CCSS.RI.5.5

CCSS.RI.6.5

CCSS.RI.7.5

CCSS.RI.8.5