Before going outside in the morning, many of us check a window thermometer (温度计) for the temperature. This helps us decide what to wear.

    {#blank#}1{#/blank#}. We want our food to be a certain coldness in the refrigerator. We want it a certain hotness in the oven. If we don't feel well, we use a thermometer to see if we have a fever. We keep our rooms a certain warmth in the winter and a certain coolness in the summer.

    Not all the thermometers use the same system to measure temperature. We use a system called the Fahrenheit scale. But most other countries use the Centigrade scale. Both systems use the freezing and boiling points of water as their guide. {#blank#}2{#/blank#}.

    The most common kind of thermometer is made with mercury inside a clear glass tube. As mercury (or any other liquid) becomes hot, it expands. As it gets colder, it contracts. That is why on hot days the mercury line is high in the glass tube. {#blank#}3{#/blank#}.

    First, take a clear glass juice bottle that has a cap; fill the bottle with colored water. Tap a hole in the center of the cap using a hammer and thick nail. Put the cap on the jar. Then stick a plastic straw through the nail hole.

{#blank#}4{#/blank#}.

    Finally, place a white card on the outside of the bottle and behind the straw. Now you can see the water lever easily.

    {#blank#}5{#/blank#}. As the temperature goes down, the water will contract, and the lever in the straw will come down. Perhaps you will want to keep a record of the water lever in the straw each morning for a week.

    Last year I ruined (毁) my summer vacation by bringing along a modem convenience that was too convenient for my own good: the iPad. Instead of looking at nature, I checked my email. Instead of paddling a small boat, I followed my Twitter feed (推特简讯). Instead of reading great novels, I stuck to reading four newspapers each morning. I was behaving as if I were still in the office. My body was on vacation but my head wasn't.

    So this year I made up my mind to try something different: withdrawal (退出) from the Internet. I knew it wouldn't be easy, since Fm bad at self-control. But I was determined. I started by giving the iPad to my wife.

    The cellphone signal (信号) at our house was worse than in the past, making my attempts at cheating an experience in frustration (沮丧). I was trapped, forced to go through with my plan. Largely cut off from email, Twitter and my favorite newspaper websites, I had few ways to connect to the world except for radio and how much radio can one listen to, really? I had to do what I had planned to all along: read books.

    This experience has had a happy ending. With determination and the strong support of my wife, I won in my vacation struggle against the Internet, realizing finally that it was I, not the iPad, that was the problem. I knew I had won when we passed a Starbucks and my wife asked if I wanted to stop to use the Wi-Fi. “I don't need it,” I said.

    However, as we return to post-vacation life, a harder test begins: Can I continue when Fm back at work? There are times when the need to know what's being said right now is great. And I have no intention (愿望) of giving up my convenience completely. But I hope to resist (抵抗) the temptation (诱惑) to check my email every five minutes, which leads to checking my Twitter feed and a website or two.

    I think a vacation is supposed to help you reset your brain to become more productive. Here I hope this one worked.

    An 18-year-old US girl gained unexpected appreciation and a surprise after she gave “extra help” to an elderly man in the restaurant she was working.

    It's social media that made her seemingly small action go viral and brought her appreciation from hundreds of thousands of strangers and a scholarship to Texas Southern University.

    The heroine Evoni Williams has reportedly been working full-time to earn money for further study in a restaurant in La Marque, Texas，the United States. It was last week when an old man named Adrian Charpentier asked for help to chop his ham for his hands were weak because of illness. On that busy morning when she had loads of work on shoulder, Williams helped the man without hesitation. The moment she was leaning over the counter and cutting the ham was shot by a customer known as Laura Wolf.

    Wolf posted the picture on the Internet and wrote, “I'm thankful to have seen this act of kindness and caring at the start of my day while everything in this world seems so negative. If we could all be like this waitress and take time to offer a helping hand…” According to local reports, Wolf didn't know Williams, neither did Williams know her act was shot and shared on the web. However, the small act of kindness soon accumulated its own power on and outside the Internet.

    Besides praise from netizens and media reports across the United States, a 16000-dollar scholarship to Texas Southern University was recently granted to Williams to support her study plan on business management.

    “We wanted to reward Evoni's act of kindness and let her know that good deeds do not go unnoticed,” said Melinda Spaulding, an administrator at Texas Southern University.

    My friend Susan has a huge-hearted husband. He is once again on the front lines of fighting the fires in Northern CA. As a Chief Battalion leader, his job is very dangerous and his time away from his family is often for weeks at a time during "fire season".

Every time before he leaves, Ethan, Susan and each of the three teens hold one another and thoughtfully each shares the best of their traditions — each promises to do the tasks that will keep the family a well-oiled machine while Ethan is away.

    Ethan has brought back animals that lost their homes in the fires. By now, a gray rabbit, two parrots and a small group of Nubian goats have been added into the family.

    When Ethan is on duty, Susan keeps checking her cell phone for Ethan's text messages. His substantial (大量的) white facial hair is often mistaken for that of Father Christmas by children who are carried out of their burning homes by him.

    For each rescued child, a toy bear is waiting to be matched with him/her. For each adult, Ethan provides clean clothes. He finds pleasure in doing his job well. He is grateful to be often on the front line with frightened people and their poor pets.

    I am mentioning Ethan because by now the big fire has been spreading widely for a week. It has caused 55 deaths and left 500,000 people homeless. Now I am here at my school site, and the smoky air is keeping our students inside, waiting for rescue.

    Put an ice cube from your fridge into a glass of water. You have a piece of string (线) 10 centimeters long. The problem is to take out that piece of ice with the help of the string. But you must not touch the ice with your fingers.

    You may ask your friends to try to do that when you are having dinner together. There is a saltcellar on the table. You must use salt when you carry out this experiment.

    First you put the string across the piece of ice. Then put some salt on the ice. Salt makes ice melt (融化). The ice round the string will begin to melt. But when it melts, it will lose heat. The cold ice cube will make the salt water freeze again.

    After a minute or two you may raise the piece of string and with it you will raise your piece of ice!

    This experiment can be very useful to you. If, for example, there is ice near the door of your house, you must use very much salt to melt all the ice. If you don't put enough salt, the water will freeze again.

    People have been wondering why elephants do not develop cancer even though they have lifespans (寿命) that are similar to humans, jiving for around 50 to 70 years.

    Now scientists believe they know why. A team at the University of Chicago, US has found that elephants carry a large number of genes that stop tumors (肿瘤) developing. To be precise, they found 20 copies of an anti-tumor gene called TP53 in elephants. Most other species, including humans, only carry one copy.

    According to the research, the extra copies of the gene improved the animal's sensitivity to DNA damage, which lets the cells quickly kill themselves when damaged before they can go on to form deadly tumors.

    "An increased risk of developing cancer has stood in the way of the evolution of large body sizes in many animals," the study author Dr Vincent Lynch told The Guardian. If every living cell has the same chance of becoming cancerous (癌变的), large creatures with a long lifespan like whales and elephants should have a greater risk of developing cancer than humans and mice. But across species, the risk of cancer does not show a connection with body mass.

    This phenomenon was found by Oxford University scientist Richard Peto in the 1970s and later named "Peto's paradox (悖论)”". Biologists believe it results from larger animals using protection that many smaller animals do not. In the elephant's case, the making of TP53 is nature's way of keeping this species alive.

    The study also found that when the same genes were brought to life in mice, they had the same cancer resistance as elephants. This means researchers could use the discovery to develop new treatments that can help stop cancers spreading or even developing in the first place.

    "Nature has already figured out how to prevent cancer," said Joshua Schiffman, a biologist at the School of Medicine, University of Utah, US. "It's up to us to learn how different animals deal with the problem so that we can use those strategies to prevent cancer in people."