According to a new survey, students' safety has become a big problem. Nearly 50% of students say they are worried about robbery on the way to and from school. Now in main big cities in China, some schools have taught an unusual lesson: self-protection. Students like this lesson because there are no exams or boring classes. And they can learn how to save lives and know how to stop danger before it really happens.

      Chen Haoyu, a teacher at Beijing No. 25 Middle School, gives young students advice on how to deal with danger.

★If you are robbed

     Keep calm. lf you can not cry for help or run away. Give the robber your money. Try to remember what the robber looks like and tell the police later.

★If you are in a traffic accident

     If a car hits you. You should remember the car number. If it is a bicycle, try to call your parents before you let the rider go. This is because you don't know how seriously you are hurt

★If it is raining hard and there is lighting

    Don't stay in high places and stay away from trees.

★When there is a fire

    Get away as fast as yon can. Put wet things on your body and try to find an exit. Do not take the lift.

★If someone is drowning

     If you can't swim, don't get into the water. Cry out for help.

      Remember that danger is never as far away as you think. Take care of yourself at all time!

    Have you ever had trouble sleeping in a new place?

    Lots of people do. And now researchers from Brown University in Rhode Island think they know why. They found that one-half of the brain "remains more awake" than the other half when people are trying to sleep in a new place.

The sleep findings were reported in Current Biology by Brown University. In their report, the researchers said many people report they have a harder time sleeping the first night at a hotel or other places outside their home. They call it "first-night influence". "In Japan they say, 'If you change your bed, you can't sleep,'" said Yuka Sasaki, one of the report's writers. "You don't sleep very well in a new place. We all know about it."

    The researchers measured brain waves (测量脑波) for 35 volunteers over two nights in a laboratory. The two nights were a week apart (间隔). They found during the first night the left half of the brain was more active than the right half. This was during the first deep-sleep period, the researchers said.

    Sasaki said a lot of questions remain.

    Researchers did not keep measuring brain waves all night long. So, they don't know if the left half keeps "watch" all night, or whether it "works in shifts (轮换) with the right half later in the night". They also do not know why the brain activity, at least during the first period of deep sleep, is always on the left half.

    For some, this research may be calming. It is good to know that our brain is "looking out for us" in a new place. But it may not help with sleep. That brain activity, at least according to this new research, makes it harder to get the sleep people need to wake up well rested in the morning.

    People already know a lot about animals. However, there are still some things about animals that may surprise you. Here are some facts about animals you probably didn't know.

    Cows do have best friends and feel stressed when they are separated. Scientists have found that cows are very social animals and a cow always makes friends with other cows. When a cow is with its friends, it feels relaxed, compared with when it is alone.

    During breeding season, a male penguin(企鹅) will offer a small stone to a female penguin as a gift. If she takes it, they will become partners. When the female penguin lays an egg, she and her partner may carry it on their feet, because some penguins don't build nests(鸟巢).

    Crocodiles(鳄鱼) swallow(吞) stones. Crocodiles always swallow their food instead of eating it like other animals. They swallow stones which break the food into very small pieces in their stomachs. These stones may stay in their stomachs all their lives.

    Elephants use plants to treat pain or other illness. Scientists once found a pregnant (怀孕) elephant in Africa who ate a kind of plant which was not part of her normal food. Four days later, she gave birth to a baby elephant. The same plant was used by the local pregnant women.

    Have you ever heard robot fish? Scientists will put some robot fish into the sea near Spain. These robot fish will help people to detect (探测) the pollution in the water. If the robot fish are able to finish their work successfully, the scientists hope to put them into rivers, lakes and seas around the world.

    The fish are about 1.5 meters long. There will be a detector in their bodies. They can find the sources (来源) of pollution in the water, and then the robot fish will eat part of it. Unlike other robots, they don't need to be controlled by people far away. The robot fish all have an eight-hour battery (电池). They can "swim" in the sea freely and send back information to people on the beach. After their batteries die, they will return by themselves.

    There are five robot fish altogether now. Each costs about 29,000 dollars. They are part of a three-year project between engineering company BMT Group and Essex University in southeastern England.

    "We invented the robot fish creatively. We hope them can find the changes in the sea water and report back the information," said Professor Hu of Essex University. His team is developing the fish.

    Today there are robots working in factories. Some can help to build cars, and they do easy jobs over and over again. Few people will do such jobs in the future because they are boring, but robots will never get bored.

    Scientists are now trying to make robots look like people. Some robots in Japan can walk and dance. However, some scientists believe that it will be difficult to make them really think like people. For example, scientist James White thinks that robots will never be able to wake up and know where they are. But many scientists don't think so. They think that robots will even be able to talk in 25 to 50 years.

    Some scientists believe that there will be more robots in the future. These new robots will look very different. Some will look like people, and others might look like animals. In India, for example, scientists made robots that look like snakes. When buildings fall down with people inside, these snake robots can help look for people under the buildings. This was not possible 20 years ago, but computers and rockets also seemed impossible 100 years ago. We never know what will happen in the future!