(18)-(20) A Toy Made from a Spring
There are many inventions in the world, and they have made our lives richer and more interesting. Thomas Edison repeated experiments and finally achieved his original goal of inventing the light bulb. Some inventions, like Edison’s light bulb, are the result of the inventor’s desire to create them from the beginning. ( 18 ), there are other types of inventions that were created by chance. A toy called the Slinky is one of them.
Richard James was an engineer working for the United States Navy. He was given the task of coming up with an idea to protect expensive instruments on the ship during the rough ocean travel. One day, while he was dealing with a spring, he ( 19 ) from a shelf. Instead of falling where he thought it would, it moved along the shelf. It looked as if it was walking down the stairs. He let the spring fall to the floor again and again to check that it moved like a living thing each time.
After showing his wife his interesting discovery, he decided to develop it into a toy. She thought about the name that would suit the toy. She looked up some words in the dictionary and chose the word slinky. She chose the name because it meant “elegant and smooth movement.” When James tried to demonstrate and sell it at a department store, he was worried. He thought that ( 20 ). However, when he arrived, many shoppers were there to buy the toy. Ever since then, the Slinky has been enjoyed by many children around the world.
(21)-(23) Learning from Owls
Owls are active at night because darkness works to their advantage. They have large eyes to gather as much light as possible. This helps them spot animals in the dark. What helps them find animals in the dark is not only their eyes but also their ears. Their ears are located at different heights on the left and right sides of their heads. This makes the time at which ( 21 ) different. They analyze this difference instantly and determine the accurate position of the animals.
Spotting food is only the first step when animals hunt for their food. The hunters must get closer and catch their food before being noticed. Owls are also good at this. Many birds tend to make noise when cutting through the wind because air moves through their feathers in uncontrolled ways. However, the edges of owl feathers are unique. The special design helps create ( 22 ). This allows them to fly quietly and long distances without being noticed.
Some researchers are considering using the owl’s feather structure in airplane design. A team at the University of London made a copy of owl feathers with 3D printing. They created model airplane wings with a structure similar to that of owl feathers and studied how air flowed around them. The research could help reduce noise from airplanes. This is very important for people in areas near airports, where more flights have caused higher noise levels. ( 23 ), many people hope for progress in this technology.
(24)-(26) E-mail
Dear marketing course participants,
Thank you for applying for the marketing course. Before your first lesson, we’d like to give you some essential information. In the first session, we’ll talk about today’s marketing needs. To help you understand, please watch a fifteen-minute video of basic concepts and practical examples before the first class on April 6. After watching it, there will be a short quiz to test your understanding.
We will have lessons every Tuesday and Thursday in April and May at 7 p.m. However, there will be a slight change in the schedule because the instructor of this course will be away for one week to attend an international conference. So, two classes for that week will be held in June. Due to this change, the course will end on June 6.
If you miss a lesson, we offer a way to catch up. We’ll post videos of each lecture on the web. However, we allow you to take this offer only twice during the course period because discussing the materials with your classmates is an important part of this class. When you miss three sessions or more, please talk to your manager. We look forward to seeing you soon !
Sarah Freeman
Marketing Course Administration
(27)-(31) The Mirror Test
Humans and animals are different in many ways. Some say only humans can have a language and a culture. Among these discussions, one idea that is often discussed is whether only humans can recognize or tell the difference between themselves and others. The mirror test is used to judge this. It is done by putting a mark on an animal’s body. The mark is put in a place where the animal cannot see without the help of a mirror. If the animal tries to remove the mark on its body, it shows that the animal recognizes itself.
The same test was done on fish called cleaner wrasses in a tank with a mirror. At first, they attacked their reflection. This could be because they thought the reflection was another fish. Later, they changed how they swam and checked if the fish in the mirror also changed how they swam. After they got used to the mirror, they were put to sleep, and a mark was put on them. When they woke up and looked in the mirror, many of them tried to take the mark off their body. They did so by brushing their body against the tank and the sand on the bottom.
They also recognized themselves in photographs. In a test done after the mirror test, researchers showed the fish some pictures. When they were shown a picture of themselves with a mark on their body, they tried to remove the mark from their body. However, they did not act the same way when pictures of other fish with a mark were shown. This suggests that they recognize differences between themselves and other fish.
The mirror test has led to much discussion and debate. First, animals that have not seen a mirror before might not understand that what is in the mirror is themselves. It does not suggest that they do not recognize themselves. Instead, it shows that they have no idea how a mirror works. Moreover, vision is not the main sense for all animals, so failing the mirror test does not always mean they cannot recognize themselves.