RI 6.3: ANALYZING KEY IDEAS

RI 6.3: ANALYZING KEY IDEAS

Multiple Choice

The Mysterious Glow of the Firefly

Fireflies (also called lightning bugs) are found in many damp regions of Asia and the Americas. There are about 2,000 different species of firefly. But how do these insects, which are actually a type of beetle, produce light, and why do they do it? Under the firefly's abdomen there is a special organ for producing light. When the insect takes in oxygen, it is combined in special cells with a substance called luciferin, and this makes that part of their bodies glow. This light gives off almost no heat.

The fireflies' glow is necessary for their survival. For one thing, the blinking light is used to lure their prey. It is also used as a warning sign to scare off predators. Perhaps the most essential purpose of the firefly's glow is to attract a mate. If you ever watch fireflies, you will see that their light flashes in various patterns, rather than steadily. Each species has a unique pattern of flashing. Because of this unique pattern, fireflies are able to find mates within their own species. Scientists have not yet discovered how fireflies can turn the glow on and off.

What is one effect of fireflies' flashing light?

• oxygen taken in from the air

• giving off heat and light

• protection from predators

• creation of luciferin

Multiple Choice

Historic Day at Kitty Hawk

December 17, 1903, was a mighty big day in the history of flight. Sailing over a beach in Kitty Hawk, North Carolina, Orville Wright piloted the first engine-powered airplane. He flew just 20 feet above the sands, and the 120-foot flight took all of 12 seconds. The Wright Brothers made three additional flights that day. Wilbur Wright's was the longest, flying a record 59 seconds and covering 852 feet.

The two brothers had been bicycle mechanics in Dayton, Ohio. Then, in 1896, they started trying to build flying machines. They chose the beach at Kitty Hawk for their test runs because of the steady winds there, which would give their flying machine some lift. Before trying to build a powered machine with an engine, they first made hundreds of runs in a non-powered glider. This taught them what they needed to know about the science and physics of flight.

Inventing a powered flying machine that could be controlled by the pilot was harder than the brothers thought. Engines made by carmakers were either not powerful enough or they were too heavy. For this reason, the Wright Brothers finally opted to design and build their own. All their hard work paid off on that December day at the beach in Kitty Hawk, though only a handful of people were there to see it. They had even told a number of newspapers that they would be trying to make history that day. However, only the local paper reported the big event.

The passage says that the Wright Brothers had trouble finding the right engine for their plane.

This caused the brothers to

• build their own airplane engine.

• give up on building a powered plane.

• pay a lot more money to buy an engine

• hire an auto mechanic to build the engine.

Multiple Choice

The Home Run King

Babe Ruth was a legendary baseball player, perhaps the greatest player who ever lived. "The Bambino," as he was sometimes called, was born in Baltimore, Maryland, in 1895. He had a difficult childhood and seemed to only feel at home on the baseball diamond. His teachers noticed his talent, and they encouraged him to play. In 1914, Babe's teachers talked the owner of the Baltimore Orioles into letting him try out. The Orioles took him on, but later that season, they traded him to the Boston Red Socks as a pitcher.

Seeing how well Babe Ruth hit a ball, the Red Socks made him an outfielder instead so he'd get to bat in every game (pitchers don't always bat). That turned out to be a very smart decision, as Babe hit a record twenty-nine home runs that season. Then he was traded to the New York Yankees where he hit fifty-four homers one year and fifty-nine the following year!

At the time, the Yankees didn't even have their own stadium. Instead, their home games had to be played at the Polo Grounds, which they rented. Babe's amazing ability to hit home runs changed all of that. He drew thousands of fans and turned his team into a successful ball club. What's more, the money the crowds brought in meant that the Yankees could afford to build their own baseball park. It was called Yankee Stadium, but was nicknamed "the house that Ruth built."

According to the passage, what was one effect of the Yankees not having their own ballpark?

• They had to rent the Polo Grounds.

• Babe Ruth did not want to play for them.

• They couldn't charge as much for tickets.

• They had fewer chances to practice.

Multiple Choice

The Mysterious Glow of the Firefly

Fireflies (also called lightning bugs) are found in many damp regions of Asia and the Americas. There are about 2,000 different species of firefly. But how do these insects, which are actually a type of beetle, produce light, and why do they do it? Under the firefly's abdomen there is a special organ for producing light. When the insect takes in oxygen, it is combined in special cells with a substance called luciferin, and this makes that part of their bodies glow. This light gives off almost no heat.

The fireflies' glow is necessary for their survival. For one thing, the blinking light is used to lure their prey. It is also used as a warning sign to scare off predators. Perhaps the most essential purpose of the firefly's glow is to attract a mate. If you ever watch fireflies, you will see that their light flashes in various patterns, rather than steadily. Each species has a unique pattern of flashing. Because of this unique pattern, fireflies are able to find mates within their own species. Scientists have not yet discovered how fireflies can turn the glow on and off.

What causes the firefly to be able to produce light?

• the need to find a mate

• a unique pattern of flashing

• a substance called luciferin

• about 2,000 different species

Multiple Choice

The Beginning of Farming in Africa

Before the people of Africa ever began farming, they gathered wild vegetables and hunted animals for meat. But by 6000 BC, the climate had gradually become very hot and dry. In fact, it was so dry that the Sahara Desert had begun to take over the grasslands. The result was that many African peoples found it harder to find the foods they were used to eating. The only way to survive was to begin growing some of their own crops. This was the start of farming in Africa.

The Sudan is south of the Sahara Desert. A similar climate change occurred in this area of Africa. With the hotter, drier weather, people had to start farming; otherwise there would have been no food to eat. While people grew wheat and barley in other parts of Africa, the climate was more extreme here because it was close to the equator, making it too hot to grow these crops. So instead, these West African peoples started growing other grasses that could stand the heat, such as millet. They used millet to make bread or mush for their meals.

The area just south of the Sudan is mainly rainforest. Here, it was impossible to grow grasses or grains to eat because it was too wet and the vegetation was too dense. People in this region of Africa learned to raise root vegetables instead, especially yams (sweet potato). Yams became the main food they ate.

What caused the people who lived south of the Sudan to begin growing yams

• The climate was too wet to grow grasses or grains.

• The temperature was hot and the ground was scorched.

• They got tired of only eating wheat and barley.

• The soil was too dry to grow millet with success.

Multiple Choice

During the Roman Empire, each time the Roman army conquered a town, it was added to the republic. Cities in the empire became larger very quickly. As a result, it soon became hard for people to get enough clean water for drinking and washing. A well in the middle of town was no longer enough, and river water was often too dirty. The government in Rome and in other cities decided to do something to help. They began building channels of stone to carry water from the hills into the towns. These were called aqueducts, from the Latin words for water (aqua) and for channel (ductus).

One of the great aqueduct systems in Europe was in the city of Rome itself. From 312 BC to 226 AD, a total of 11 aqueducts were built to bring water to Rome. These were very challenging for engineers to design and build. The water had to be able to reach the city without stagnating (standing still for too long) or running too fast. The engineers sometimes had to run the aqueducts over high arches or through underground tunnels. This was done in order to regulate the flow of water.

These ancient aqueducts were so effective that they were used for a few hundred years, until the 400s AD. At that time, the fall of the Roman Empire in Europe changed how people lived. Towns became much smaller again, in many places. This meant that people could again get the water they needed from local wells. The great arches of the aqueducts can still be seen in parts of Europe portions of them are still in use today.

According to the passage, what caused city governments to build aqueducts?

• not enough people living in the cities

• the fall of the Roman Empire

• underground tunnels falling apart

• larger populations needing fresh water

Multiple Choice

Training for a Marathon: Pre-Training Is Key to Success

Like climbing a mountain, running a marathon is something many people want to be able to say they've done. A marathon is 26.2 miles long. If you have a dream of running one someday, just remember one word: pre-training.

Before you even start to train for the big race, you first need to be able to run for half an hour without stopping. Don't worry about how far you run at this point. The main thing is to first get your body used to running. Many athletes who skip this pre-training step and jump right into intense training never make it to the marathon. They burn out or exhaust or injure themselves because their bodies weren't ready for long distances. During the pre-training time, one good method is to combine walks and runs so that you're running for a bit, then walking, then running again. This is a great way to build strength and endurance. Easing into an exercise program like this will also greatly reduce the possibility of injuring yourself.

Once you can run for 30 minutes at a stretch, it's time to sign up and register for the marathon! Doing so will help keep you motivated to stick to your training schedule as you dream of the big day. There are plenty of websites that will outline an intensive training program, including what foods to eat. The more you run, the more calories you will burn, so you will need to eat more food to compensate. Also, make sure you talk to your doctor before beginning this or any exercise program. If he or she gives you the green light, then post that training schedule on the fridge, grab your music player, and hit the track!

When pre-training for a marathon, what is one effect of a walking/running program?

• It's harder on your body.

• It increases risk of injury.

• It makes you run faster.

• It builds endurance.