Elephants on the coast of Thailand are acting strange.They stamp their feet and motion toward the hills.The sea draws back from the beaches.Fish fall heavily in the mud.Suddenly,a huge wave appears.This is no ordinary wave.It is tsunami!

    Tsunami waves are larger and faster than normal surface waves.A tsunami wave can travel as fast as a jet plane and can be as tall as a ten-story building.Imagine dropping a stone into a pond.The water on the surface ripples（起涟漪）.A tsunami is like a very powerful ripple.Tsunamis begin when the ocean rises or falls very suddenly.Large amounts of seawater are displaced.This movement caused huge waves.

    For a tsunami to occur,there must be some kind of force that causes the ocean water to become displaced.Most tsunamis are caused by underwater earthquakes.However,volcanoes ,landslides（塌方）,large icebergs,and even meteorites（陨石）are capable of causing one of these mighty waves.

    Tsunamis are extremely powerful.Ordinary waves lose power when they break.Tsunami waves can remain powerful for several days.Because tsunami waves are so strong,they can kill people,damage property,and completely ruin an ecosystem in just one hour.

    Scientists have no way of predicting when a tsunami will hit.However,if a powerful enough earthquake occurs, scientists can send out a warning or a watch.A warning means that a tsunami will very likely hit soon.A watch means that conditions are favorable for a tsunami.When people are informed of a watch or a warning,they have more time to prepare.It is best not to get caught unaware when a tsunami is on the way.

    Scottish pupils recently were part of a new scheme that allowed them to take their exams online. Those examinations provided a glimpse of the future in May when 120 candidates in 10 centers in Scotland sat in front of computers to take a multiple-choice online exam. Although candidates were using a computer mouse instead of a pen, in all other ways the exam was the same as normal.

    Exam rooms were set out to ensure that only the candidates and the teachers were able to see the individual screens. The online answers were sent directly to a safe area. According to the students at St Ninian's in East Renfrewshire who took an online French exam, it was definitely the most motivated they had ever felt when taking an exam.

    “I could go as fast as I wanted to, rather than as slow as everyone else wanted to,” said one. “It was better than looking back and forth between the questions,” said another. One pupil even described it as fun.

    Their head teacher, Dorothy Graham, was not so surprised, “They are so used to doing things on computers that it seems natural for them. The boys liked it because they didn't have to worry about how neat their work was.” The only things that worried her were power cuts and systems' crashing.

    It's thought that online exams could be the norm (常态) in about five years. However, last year there were warnings about computerizing exams in England and Wales. It's thought that it could be unfair to some students if they come from homes without access to a computer.

    Do you ever dream about climbing Mount Everest, which is 8,848 meters high? If so, you're not alone. Every year, thousands of people try to climb the world's highest mountains or walk across deserts. Let's take a look at some of the 21st century's greatest adventurers (冒险家).

    Ed Stafford

    Ed Stafford from the UK is the first person to walk along the Amazon River from the mountains of Peru to the mouth of the river in Brazil. There are many dangerous animals in the rainforest, but he was only bitten by ants and mosquitoes. On his trip, Ed had to find fruit and nuts or catch fish each morning. He used a radio to ask the people of the rainforest for food and help. Many people came to meet him and guide him through the rainforest. While he walked, Ed wrote a blog to tell the world about climate change and destruction (破坏) of the rainforest.

    Gerlinde Kaltenbrunner

    Gerinde Kaltenbrunner from Austria is one of the world's greatest climbers and has climbed all the world's mountains over 8,000 metres. It's very difficult to climb in the cold weather and storms, but Gerlinde loves it. Now she spends her time climbing and helping a charity for poor children in Nepal.

    Meagan Mcgrath

    Some adventurers are always looking for a new challenge. Meagan Mcgrath from Canada has climbed mountains, ridden a bike across Canada and run races in the desert to raise money for the disabled.

    Erik Weihenmayer

    Erik Weihenmayer from the United States has climbed mountains and ridden a bike through deserts. Amazingly, Erik is blind and he wants other blind people to have active lives too. He has taken groups of young blind people climbing in Nepal.

    Toronto is reminding citizens this month what exactly can and can't go into the blue bins an you may be surprised at what can't be recycled. As it turns out the takeout coffee cups you've been throwing into the recycling actually have to go in the garbage.

    The city's “recycle right” web explains that food left after a meal, woven (编织的) cloth, old VHS tapes and other things have been turning up in blue bins, where they don't belong.

    According to the city, about 45,000 tunes of garbage was mistakenly put into recycling bins last year alone.

    Among those things are the takeout coffee and tea cups we get while were on the go. The city says that because those paper cups are lined with plastic or wax they can't be recycled. The black plastic coffee lids (盖子) also can't go in the blue bin, although non-black plastic lids can be recycled.

    Emily Alfred, senior campaigner with the Toronto Environmental Alliance, said, “Millions of cups are used in Toronto every year and people are taking these out and putting them in the wrong bin.”

    When paper coffee cups are thrown in with the recycling. Alfred said, they produce a harmful effect on the system.

    “They can't separate the plastic and paper in a typical paper recycling center,” Alfred said, “so it just causes pollution of the recycling process, and it causes lower-quality paper if it does get recycled.”

    “New regulations passed last month call for changes to be rolled out over the next few years regarding what products companies can sell,” Alfred said. Her organization will be pushing for more producer responsibility laws, which call on companies that design and make products to take on the responsibility of recycling them.

    For now, consumers can consider carrying their own reusable coffee cups while they are on the go, ask for a ceramic mug (陶瓷杯) if they plan to consume their drink in the cafe, and support their local government officials if they have put efforts into changing recycling or producer responsibility laws.

    Alfred said, “I think people can change their habits easily if they understand what to do.”

    A study examining the children of people evacuated(撤离) during the WWII showed the daughters of female evacuees were up to four times more likely to suffer from serious mental health conditions compared to those whose parents stayed at home.

    In the largest enquiry ever of its kind, researchers examined the health records of 3000 children of Finnish people evacuated to Sweden during the 1941-1945 conflict with Soviet Russia. The evacuees, many of whom were at a pre-school age, were placed with foster families in Sweden and were forced to learn Swedish, later returning to Finland. The study found that the female children of these girls had an increased risk of being hospitalized for conditions such as depression. However, this was not the case with children of boys evacuated during the war.

    The study could not determine why. One possibility is that the stress of the evacuees' experience affected their psychological development in ways that influenced their parenting style. Another possibility is that the evacuees' experience resulted in epigenetic changes—changed in the way genes are expressed. For example, the researchers mentioned an earlier finding that Holocaust survivors have higher levels of methyl groups bound to the FKBP5 gene and have passed his change on to their children. This higher level of methyl groups appears to change the production of cortisol, a hormone(荷尔蒙) that controls the stress response.

    "The Finnish evacuation was intended to protect children from the harm associated with the country's wars with the Soviet Union", said study co-author Dr Torsten Santavirta, from Uppsala University.

    "Our observation of the long-term psychiatric(精神病的) risk that reached into the next generation is concerning and stresses the need to weigh benefits as well as potential risks when designing policies for child protection".

Have you ever heard of invisible ink? You may have seen it in movies. When light is shone on the paper which invisible ink is written on, you can read it!

As magical as this seems, the change in color is due to science. The ink is absorbing higher energy light and giving lower energy light. This reaction is an example of fluorescence (荧光) .

Light is a very broad term that describes a range of electromagnetic rays, including gamma rays, infrared light (红外光) and ultraviolet light. One part of the electromagnetic visible light is the colors that we can see with the human eye. These rays travel in curvy lines and each type of the ray is characterized by a different wave pattern. For example, Gamma rays have a shorter wavelength than infrared light. Shorter wavelength is connected with higher energy, so gamma rays also have more energy than infrared light.

Corals (珊瑚) are animals that live underwater. And the corals in the Red Sea exhibit fluorescence. Why is this happening? Scientists have shown that fluorescent objects absorb higher energy light and release lower energy light. Since the corals of the Red Sea are deep in the water where there is very little visible light, scientists theorize that these corals absorb ultraviolet light and produce visible light. They have special photo proteins, which enable them to change invisible light to visible light.

Fluorescence is not just used to create pretty colors. Corals have developed photo proteins for a biological reason. The visible light is used by algae (海藻) , which are eaten by the coral, to make food through photosynthesis (光合作用). The visual character of these photo proteins could also be used for biomedical research. They can highlight cells and cell structures under a microscope.

Isn't it amazing that a simple organism that we don't think very much of is not only grand but could also have so many potential uses in medical research!