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.

    Life in the Clear

    Transparent animals let light pass through their bodies the same way light passes through a window. These animals typically live between the surface of the ocean and a depth of about 3,300 feet—as far as most light can reach. Most of them are extremely delicate and can be damaged by a simple touch. Sonke Johnsen, a scientist in biology, says, “These animals live through their life alone. They never touch anything unless they're eating it, or unless something is eating them.”

    And they are as clear as glass. How does an animal become see-through? It's trickier than you might think.

    The objects around you are visible because they interact with light. Light typically travels in a straight line. But some materials slow and scatter(散射) light, bouncing it away from its original path. Others absorb light, stopping it dead in its tracks. Both scattering and absorption make an object look different from other objects around it, so you can see it easily.

But a transparent object doesn't absorb or scatter light, at least not very much, Light can pass through it without bending or stopping. That means a transparent object doesn't look very different from the surrounding air or water. You don't see it —-you see the things behind it.

    To become transparent, an animal needs to keep its body from absorbing or scattering light. Living materials can stop light because they contain pigments(色素) that absorb specific colors of light. But a transparent animal doesn't have pigments, so its tissues won't absorb light. According to Johnsen, avoiding absorption is actually easy. The real challenge is preventing light from scattering.

Animals are built of many different materials—-skin, fat, and more—-and light moves through each at a different speed. Every time light moves into a material with a new speed, it bends and scatters. Transparent animals use different tricks to fight scattering. Some animals are simply very small or extremely flat. Without much tissue to scatter light, it is easier to be see—through. Others build a large, clear mass of non-living jelly-lie(果冻状的)material and spread themselves over it .

    Larger transparent animals have the biggest challenge, because they have to make all the different tissues in their bodies slow down light exactly as much as water does. They need to look uniform. But how they're doing it is still unknown. One thing is clear for these larger animals, staying transparent is an active process. When they die, they turn a non-transparent milky white.

    Kulangsu Gallery of Foreign Artefacts from the Palace Museum Collection

    Location: Kulangsu, Xiamen, Fujian Province

    Dates: May 13, 2018 through September 24, 2018

    The gallery is a major place for the Palace Museum to showcase its splendid collection of international art. Most of these works have been kept in the storehouse of the museum and have never been shown to the public. Originally from Europe, East Asia, and North America, these international works date from the sixteenth to the twentieth century.

    Exhibition Commemorating the 120^th Anniversary of Zhang Boju's Birth

    Location: Hall of Martial Valor (Wuying dian)

    Dates: April 3, 2018 through May 6, 2018

    The exhibition features traditional Chinese paintings and calligraphy from state-owned museums. Divided into three sections, the exhibition displays artwork organized in order of time, which offers a comprehensive overview of Zhang Boju's collection through this impressive gathering of the collector's works.

    Discovering the Hall of Mental Cultivation

    Location: The Gate of the Correct Department (Duan men)

    Dates: April 3, 2018 through April 24, 2018

    The exhibition allows visitors new ways to explore the history of the forbidden city with a simple click and celebrates the 92^nd anniversary of the establishment of the Palace Museum, established on October 10, 1925. Adding to the museum's new displays, this exhibition combines traditional Chinese culture and contemporary technologies.

    Treasures from the Al Thani Collection

    Location: The Meridian Gate (Wu men)

    Dates: April 17, 2018 through July 18, 2018

    The Al Thani Collection allows visitors to see cultural landscapes that have been lost in the depths of history. Artefacts from Egypt and Persia throw light on mysteries known to few. Different peoples have marked these relics with their own styles, which reflect the unique sources of each culture but strike the viewers with an equally powerful charm.

    Google's new camera, called Clips, is a small, smart device. It comes with a case that has a clip (夹子), but it's not designed to be worn on your clothing. Most interestingly, it uses artificial intelligence to take photography out of your hands so it can capture moments on its own.

    This roughly 2-inch by 2-inch camera, with a three-hour battery life and Gorilla Glass for toughness, is intended for candid moments, like when a child does something cute that may happen too quickly for you to pull out your smartphone.

    Onboard the Clips device, it uses machine learning algorithms (计算程序) to help capture scenes. Those algorithms include face recognition. "Once it learns that there's a face you see frequently, it'll try to get nice photos of those faces," said Juston Payne, the device's product manager. And they also want it to recognize facial expressions, which involved "training it to know what happiness looks like". The Google team also trained it to recognize what not to shoot—like when a child's hand is over the lens, or if it is tossed in a dark purse.

    The only way to see the images is by connecting the camera with your phone, as it has no screen for viewing or editing.

    Were people concerned it could seem strange? Yes, Payne admitted. But they said they addressed that by making it obvious what it is. A green light on the front signals that it is on. Besides, unlike a camera meant to monitor your home, it is not connected to the Internet.

    "This product is only possible because of the way that silicon has advanced" Payne said, noting that it was only in the past year or so that they could squeeze the technology down into a device this size. Going forward, we're likely to get more assistance from the artificial intelligence packed into our apps and gadgets.

Unhealthy health care bills, long emergency-room waits and inability to find a primary care physician just scratch the surface of the problems that patients face daily.

Primary care should be the backbone of any health care system. Countries with appropriate primary care resources score highly when it comes to health outcomes and costs. The U.S. takes the opposite approach by emphasizing the specialists rather than the primary care physician.

A recent study analyzed the providers who treat Medicare Beneficiaries(老年医保受惠人). The startling finding was that the average Medicare patient saw a total of seven doctors — two primary care physicians and five specialists — in a given year. Contrary to popular belief, the more physicians taking care of you don't guarantee better care. Actually increasing breakup of care results in a corresponding rise in costs and medical errors.

How did we let primary care slip so far? The key is how doctors are paid. Most physicians are paid whenever they perform a medical service. The more a physician does, regardless of quality or outcome, the better he's reimbursed (返还费用). Moreover, the amount of a physician receives leans heavily toward medical or surgical procedures. A specialist who performs a procedure in a 30-minute visit can be paid three times more than a primary care physician using that same 30 minutes to discuss a patient's disease. Combine this fact with annual government threats to indiscriminately cut reimbursements, physicians are faced with no choice but to increase quantity to boost income.

Primary care physicians who refuse to compromise quality are either driven out of business or to cash-only practices, further contributing to the decline of primary care.

Medical students are not blind to this scenario. They see how heavily the reimbursement deck is stacked against primary care. The recent numbers show that since 1997, newly graduated U.S. medical students who choose primary care as a career have declined by 50%. This trend results in emergency rooms being overwhelmed with patients without regular doctors.

How do we fix this problem?

It starts with reforming the physician reimbursement system. Remove the pressure for primary care physicians to squeeze in more patients per hour, and reward them for optimally managing their diseases and practicing evidence-based medicine. Make primary care more attractive food to medical students by forgiving students loans for those who choose primary care as a career and harmonizing the marked difference between specialist and primary care physician salaries.

We're at the point where primary care is needed more than ever. Within a few years, the first wave of 76 million Baby Boomers will become qualified for Medicare. Patients older than 85, who need chronic care most, will rise by 50% this decade.

Who will be there to treat  them？

About two weeks ago I saw a very sad, blue eyed, homeless man sitting outside my local coffee house. I said, "Hi! How are you doing today?"

He seemed shocked that I was talking to him. "Not very well, " he replied. He began to tell me how he had been hit by a car while riding his bike. He had been in the hospital for a month and s rest home for another month. During that time the person that paid for his SSI checks （社保费） died of a hear attack and his wallet was stolen with all his IDs. He had several checks waiting for him but had no ID and therefore no access to his money. 

I decided that if this was all true I'd like to help him get a copy of his birth certificate and social security card. I asked him to meet me at the Department of Vital Statistics at 11: 00 p. m. The next morning I didn't see him so I started filling out the paperwork. I explained to the receptionist, "I'm trying to help a homeless friend get his ID hack. " "Bob?" she inquired. "Yes, Bob, " I responded, surprised that she knew his name. "He was here at 9: 30 and he just left, she said, "But he told us you were coming. " I paid the fee and walked out with Bob's Birth Certificate. 

As I was driving home I saw Bob riding back on the old bike someone had given him. I pulled over and jumped out of my car shouting, "Bob! Bob! I got it!" He saw me and rode over. "I got it, Bob! Look, here it is!" He got tears in his eyes and told me I was his guardian angel. 

A few days later I needed him to meet me at the Social Security Office. It took me a half hour to get there by car and at least two hours by bike. But there he was sitting on the sidewalk waiting for me! We were in the Social Security Office for two hours. We got everything straightened out and by next week he will have received his back pay, which is a substantial sum. 

Yes, one person can make a difference in this world. And the interesting thing is that I am getting as much, if not more, from this experience than Bob. I am deeply touched by Bob's sensitivity, his gratitude, his stories, his heart. 

Home is where the heart is, even for the homeless!