Air is a colorless, tasteless and invisible（看不见的）gas that is around us. An "empty" drinking glass and an "empty" room, in fact, are not really empty. Each is filled with air. When the glass is filled with water, the water pushes the air out of the glass.

    Air, as a gas, has no definite shape, but because it is matter, it takes up space and it has weight. It is easy to prove that air is something that takes up space. Stuff a piece of dry cloth（布）into the bottom of a glass so that it will not fall out when the glass is turned upside down. Push the upside down glass, holding straight up and down, into a jar of water till the glass is completely covered. When the glass is taken out of the water, the cloth is still dry. The air inside the glass shows that it takes up space and keeps the water from coming in.

    Is your TV connected to the Internet? What about your chair, or your fridge? Probably they are not. But in the future, most things in your home may be connected, thanks to the so-called "Internet of things".

    The Internet of things may be coming sooner than you think. Earlier this year, Samsung CEO spent a lot of time talking about the Internet things. He said that three years from now, every Samsung product will be part of the Internet of things, no matter whether it's a remote control or a washing machine.

    So, how do household objects that are part of the Internet of things work? Well, think of a common chair. When connected to the Internet, the chair warms up when it knows the user has just walked into the room and is feeling cold.

    An Internet-connected camera could help people feel safer in their homes. It can know people's faces and has an infrared sensor（红外传感器）, so even if it's dark it can see when someone passes by and send you a message on your smart-phone to let you know who's there. If the person is someone you don't know, it can tell you that, too.

    But according to MIT Technology Review, whether companies are connecting dog food bowls or safety systems to the Internet, there may be some problems. For example, many early connected-home objects don't have much built-in security, which means they could be hacked（攻击）. Moreover, it could be difficult to get these new machines to work together especially when they are made by different companies. To fight this, many companies have joined the Open Interconnect Consortium, which had 45 members by late 2015.

    So, picture this: you enter your home. The temperature changes to make you feel comfortable. Your favorite music starts playing for you. Do you think that this would be a good thing? It may happen sooner than you think.

    A fish that lives in America can live out of water for months at a time, similar to how animals got used to land millions of years ago, a new study shows.

    The Mangrove Rivulets, a kind of little fish, lives in small pools of water. When their living place dries up, they live on the land, said Scott Taylor, a researcher in Florida.

    The fish can grow as large as three inches. They group together and breathe air through their skin before they can find water again.

    The new scientific discovery came during a trip.

    "We were travelling for fun. And one day I kicked over a log (圆木) and the fish came out." Taylor told reporters by telephone. He said he would make his study on the fish known to the public in an American magazine early next year.

    In lab tests, Taylor said he found the fish can live up to 66 days out of water without eating.

    Some other fish can live out of water for a short period of time. The walking catfish found in Southeast Asia can stay on land for hours at a time, while lungfish(肺鱼) found in Australia, Africa and South America can live out of water, but only in a not active(活跃的) way. But no other known fish can be out of water as long as the Mangrove Rivulets and keep active, according to Patricia Wright, a biologist at a Canadian University.

    More studies of the fish may tell how animals changed over time.

    "These animals live in conditions similar to those millions of years ago, when animals began to move from water onto land." Wright said.

    Beauty sleep is a real thing, researches have shown that people who have enough sleep look more attractive (有魅力的) to others.

    A few bad nights are enough to make a person look especially "more ugly", their sleep experiments show.

    The researchers asked 25 university students to join in their sleep experiment. They were asked to get a good night's sleep for two nights.

    A week later, they were asked to sleep for only four hour every night for two nights in a row. The researchers took make—up free (素颜) photos of the volunteers after both the good and the bad sleep.

    Next, they asked 122 strangers to have a look at the photos and judge (评价) them on attractiveness, health, and sleepiness, as well as asking them: "How much would you like to make friends with this person in the picture?"

    The strangers were good at judging whether the person they were looking at was tired, and if he was sleepy, his attractiveness score would be low.

    The strangers also said they wouldn't want to socialize with the tired students. The researchers say this is natural for people. An unhealthy-looking face makes people run away. In other words, people don't want to hang around with people who might be ill.

    Dr Brewer, an expert at the University of Liverpool said: "Judgment of attractiveness is often unconscious (无意识的), but we all do it, and we are able to judge on even something small like whether someone looks tired or unhealthy. This study is a good reminder of how important sleep is to us."