You know that balloons must be kept away from sharp objects. They also needed to be kept away from flames. A fire can weaken the rubber and cause it to break. However, in this experiment you will find out how you can hold a balloon directly in a flame without breaking the balloon.

    Materials needed:

● two round balloons not inflated(充气的)

● several matches

● water

    Inflate one of the balloons and tie it. Place 1/4 cup of water in the other balloon, and then inflate it and tie it. Light a match and hold it under the first balloon. Allow the flame to touch the balloon. What happens? The balloon breaks, perhaps even before the flame touches it. Light another match. Hold it directly under the water in the second balloon. Allow the flame to touch the balloon. What happens to this balloon? It doesn't break.

    Why does the balloon with no water break in the flame? The flame heats the rubber of both balloons. The rubber of the balloon without water becomes so hot that it becomes too weak to resist the pressure of the air inside the balloon. However, when the balloon with water in it is placed in the flame, the water takes in most of the heat from the flame. Then, the rubber of the balloon doesn't become very hot, it doesn't weaken, and the balloon doesn't break.

    Water is a particularly good absorber(吸收者) of heat. It takes a lot of heat to change the temperature of water. On the other hand, when water cools, it gives off a great deal of heat. That's why areas near oceans or other large bodies of water don't get as cold in winter as areas at the same latitude(纬度) further inland.

—I _______there for three years. It's great to be back.

    While both Europe and the United States of America are considered the Western world, it's good to know there are some differences in culture. If you are considering moving to a European country, you will find the information below helpful as you plan your move.

    One cultural difference is how the countries perceive（感知）time and space. For example, a house in the United States that is 200 years old would be considered ancient. This is probably because America is a fairly young country. However, in Europe, something would not be considered ancient unless it was at least 2,000 years old. However, perception of distance seems to be the opposite. While Europeans would consider 100 kilometers a long way to drive, Americans would think twice. This could be due to the fact that Europe is smaller and more heavily populated. In fact, the United States is over twice the size of Europe.

    Cars are another factor that differs greatly between Europe and the United States. American automobiles usually have automatic transmissions（传动）while European cars generally have manual gears（手动变速器）. European automobiles are smaller and more round-shaped, while American cars are larger and more square-shaped. Trucks and limousine are vehicles that American enjoy. In Europe, however, these types of vehicles are hardly seen, as they prefer smaller cars due to parking and traffic congestion.

    The view of education is another cultural difference between the European countries and the United States. In America, parents may save for many years and even go into debt to pay for their children to attend college. Most schools and universities in Europe, however, are free of tuition. In fact, it is just expected for children to attend college there and not a privilege（特权）, as in the United States.

Plastic-Eating Worms

    Humans produce more than 300 million tons of plastic every year. Almost half of that winds up in landfills(垃圾填埋场)，and up to 12 million tons pollute the oceans. So far there is no effective way to get rid of it, but a new study suggests an answer may lie in the stomachs of some hungry worms.

    Researchers in Spain and England recently found that the worms of the greater wax moth can break down polyethylene, which accounts for 40% of plastics. The team left 100 wax worms on a commercial polyethylene shopping bag for 12 hours, and the worms consumed and broke down about 92 milligrams, or almost 3% of it. To confirm that the worms' chewing alone was not responsible for the polyethylene breakdown, the researchers made some worms into paste(糊状物) and applied it to plastic films. 14 hours later the films had lost 13% of their mass--apparently broken down by enzymes(酶)from the worms' stomachs. Their findings were published in Current Biology in 2017.

    Federica Bertocchini, co-author of the study, says the worms' ability to break down their everyday food-beeswax--also allows them to break down plastic "Wax is a complex mixture, but the basic bond in polyethylene, the carbon-carbon bond, is there as well, "she explains. "The wax worm evolved a method or system to break this bond. "

    Jennifer Debruyn, a microbiologist at the University of Tennessee, who was not involved in the study, says it is not surprising that such worms can break down polyethylene. But compared with previous studies, she finds the speed of breaking down in this one exciting. The next step, DeBruyn says, will be to identify the cause of the breakdown. Is it an enzyme produced by the worm itself or by its gut microbes(肠道微生物)?

    Bertocchini agrees and hopes her team's findings might one day help employ the enzyme to break down plastics in landfills. But she expects using the chemical in some kind of industrial process-not simply "millions of worms thrown on top of the plastic."

    Since 2013,Torobo, a robotic are designed to test the limits of artificial intelligence, has had one ambition—to be admitted to the University of Tokyo, one of Asia's top-ranked educational institutions. Although equipped with an extensive database of textbooks and other teaching materials, Torobo has repeatedly failed to obtain the university's required minimum 80% score in the National Center Test, a yearly standardized entrance examination adopted by Japanese universities. This year was no exception.

    In early November, Torobo, along with millions of Japanese high school students, took a mock(模拟的)exam to prepare for the all-important standardized test.

    Torobo's total score of 525 out of 950, which was higher than the national average, was enough for it to get admitted to many other influential Japanese universities.

    However, its standard score of 57.1%, though 14 points higher than in 2015, still fell short of the minimum required for the University of Tokyo.

    A closer analysis of the results showed that Torobo was able to draw from its database to solve knowledge-based questions and ones involving complex mathematical calculations, but it had a hard time thinking independently, failing to comprehend multiple sentences and phrases to arrive at the logical conclusions. This weakness was reflected in its shabby English scores.

    Fortunately, the robot's creators have decided to free Torobo from its four-year sufferings. Noriko Arai, professor of the University of Tokyo who heads the team, says, “From the present results, we are able to evaluate the possibilities and limits of artificial intelligence. From now on, we will grow its abilities in the fields where it is doing well and aim to improve them to levels that can be applied in industry.” So while Torobo will never graduate from the University of Tokyo, it can still look forward to a bright future!