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Inspiring young minds!

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    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.

    Hobbs was an orphan (孤儿). He worked in a factory and every day he got a little money. Hard work made him thin and weak. He wanted to borrow a lot of money to learn to paint pictures, but he did not think he could pay off the debts.

One day a lawyer said to him, “One thousand dollars, and here is the money.” As Hobbs took the package of notes, he was very dumbfounded. He didn't know where the money came from and how to spend it. He said to himself, “I could go to find a hotel and live like a rich man for a few days; or I give up my work in the factory and do what I'd like to do—painting pictures. I could do that for a few weeks, but what would I do after that? I should have lost my place in the factory and have no money to live on. If it were a little less money, I would buy a new coat, or a radio, or give a dinner to my friends. If it were more, I could give up the work and pay for painting pictures. But it's too much for one and too little for the other.”

    “Here is the reading of your uncle's will (遗嘱)，” said the lawyer, “telling what is to be done with this money after his death. I must ask you to remember one point. Your uncle has said you must bring me a paper showing exactly what you did with his money, as soon as you have spent it.” “Yes, I see. I'll do that，” said the young man.

    When I was 12, all I wanted was a signet(图章)ring. They were the “in” thing and it seemed every girl except me had one. On my 13th birthday, my Mum gave me a signet ring with my initials(姓名首字母) carved into it. I was in heaven.

    What made it even more special was that it was about the only thing that wasn't being “replaced”. We'd been burnt out in fires that swept through our area earlier that year and had lost everything—so most of the “new” stuff(东 西)we got was rally just to replace what we'd lost. But not my ring. My ring was new.

    Then, only one month later, I lost it. I took if off before bed and it was missing in the morning. I was sad and searched everywhere for it. But it seemed to have disappeared. Eventually, I gave up and stopped looking for it. And two years later, we sold the house and moved away.

    Years passed, and a couple of moves later, I was visiting my parents' when Mum told me that she had something for me. It wasn't my birthday, nor was it Easter or Christmas or any other gift-giving occasion. Mum noticed my questioning look. “ You'll recognize this one.,” she said smiling.

    Then she handed me a small ring box. I took it from her and opened it to find my beautiful signet ring inside. The family who had bought our house 13 years earlier had recently decided to do some redecorations, which included replacing the carpets. When they pulled the carpet up in my old bedroom, they found the ring. As it had my initials carved into it. They realized who owned the ring. They'd had it professionally cleaned up by a jeweler before sending it to my mother. And it still fits me.

    A disease called “Panama” is threatening supplies of the world's most popular fruit—banana.Two years ago,the United Nations warned that the "Panama disease" could destroy "much of the world's banana crop."Since then,things have not gotten better.A new outbreak was discovered last year in Australia.The disease started in Asia in the 1990s, and later spread to Africa and the Middle East.

    World health officials worry the disease could travel to Latin America,one of the top banana producers in the world.All this is a big concern because bananas are an important source of income and nutrients for millions of people.They are grown in 135 tropical nations.The United Nations lists bananas as one of the most important foods, along with rice,wheat and corn.

    Randy Ploetz is a professor at the Tropical Research & Educational Center at the University of Florida.Many consider him as America's top banana expert.As he explained,Panama disease affects the Cavendish banana.The Cavendish is one of more than 500 kinds of bananas.But it is the most popular.

    “The industry is waking up to the problem,”Ploetz said.“They are pretty scared.”He was speaking Thursday by telephone from Miami,Florida,where he is among 1,000 people attending the International Banana Congress.The meeting was supposed to take place in Costa Rica,but was moved at the last minute.There were concerns banana growers could spread Panama disease from dirt collected on their shoes,Ploetz said.

    Ploetz said reports that Cavendish banana production could end are not correct.But if the disease spreads to Latin America,it could hurt the world's economy along with food supplies for millions of people.Still,he said there is reason for hope.Scientists in Australia are working on a genetically engineered banana that might not be at risk of getting Panama disease.

    If you're a fan of smart technology, you may have had some sleepless nights lately. That's because Alexa, the artificial intelligence (AI) behind US company Amazon's Echo smart speakers, has been "letting out an unprompted (自发的),creepy (令人毛骨悚然的)cackle for no apparent reason, according to BBC News.

    Many social media users shared their stories of Alexa scaring them with the seemingly unprompted laugh.

    "Every time Alexa laughs, an angel dies," Tesla and SpaceX founder Elon Musk joked on social media.

    On March 7, Amazon released an update that fixed the problem, saying that the laugh was caused by Echo devices mistakenly thinking that users had said the command " Alexa, laugh".

    However, what should have been a funny story raised the ongoing topic of man versus machine.

    With the rise of artificial and robotic technology, "Digital machines started to demonstrate broad abilities in pattern recognition, complex communication, and other area that used to be particularly human," wrote Erik Brynjolfsson and Andrew McAfee in their book The Second Machine Age: Work, Progress, and Prosperity in a Time of Brilliant Technologies. They believe that AI will "do more and more, and our lives will get better".

    However, ever since the earliest days of AI there have been concerns that some day, software will take over the world, leaving the fate of humans unknown.

    "With artificial intelligence we are order the demon (魔鬼)Musk told students during a meeting at MIT in 2014. "If I had to guess at what our biggest existential threat is, it's probably that. So we need to be very careful

    Many scientists have shared the same concern. The late British physicist Stephen Hawking said at a technology conference in Portugal in November that "computers can. in theory, imitate human intelligence, and exceed it ••• AI could be the worst event in the history of our civilization."

    If creators are to safely control AL however, Hawking suggested that they "employ best practice and effective management".

    I am an optimist and I believe that we can create AI for the good of the world," he said at the conference. "We simply need to be aware of the dangers, identify them, employ the best possible practice and management, and prepare for its consequences well in advance."