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Find Which Direction Is South

    Do you have a good sense of direction? If not, please take with you a compass. But if you forget to take a compass, you can still find your way. 

    It's never a wise idea to believe that the family member who was good at the job of map-reading knows where the family is. You can tell by the troubled look on their faces that nothing on the ground seems to match the map. Never mind. The sun is shining and it's still morning. If you don't know the exact time, you can still find out where south is, but you'll need to be patient. 

    ①Find a straight stick and put it in the ground in a place where you can mark its shadow(a dark shape on a surface that is made when something stands between a light and the surface). 

    ②Try to position the stick as vertically(垂直)as you can. You can check this by making a simple plumb line(铅锤线). You haven't got one? OK, use a thread(线) from your clothes with a button(纽扣) tied at the end to act as a weight.

    ③Mark the end of the shadow cast(投射) by the stick.

    ④Wait about half an hour and mark the end of the shadow again.

    ⑤Keep doing this until you have made several marks. 

    ⑥The mark nearest the stick will represent the shortest shadow, which is cast at midday, when the sun is highest in the sky and pointing to the exact south. 

    ⑦Pick a point in the distance along the line between the shortest shadow and the stick.

    ⑧That point is south of where you are. 

    ⑨Now you can turn the map, like you did before, and find which way you should be travelling. 

    The Smallest Life Around Us

    Tiny plants and animals live all around us．We cannot see them because they are so small，but they are everywhere. They live in the soil，in the air，and in rivers and oceans．They grow on mountains and in caves．Some live in the ice at the north and south poles; some live where it is very hot．They are found throughout cities and in the country. They grow on other plants and animals．Some are even living on you，on your skin，hair，and inside your body，in your mouth，nose，and all through your body．

    These tiny plants and animals are called microbes．The word microbe is made from two other words：micro，meaning small，and bios，meaning life．So，microbe means small life．

    Microbes have been on earth for a very long time．They may have been the first forms of life to be alive．Today there are more microbes in the world than all other living things．

    People did not know microbes had existed（存在） long．They were too small for them to see．But people did see many changes in their world﹣important changes．And they did not know what caused them．They saw food that they kept too long change color and begin to smell bad．They saw cuts and wounds grow red and painful and become worse. They saw old plants and leaves and trees crumble apart on the forest floor and disappear into the soil．Such changes were a natural part of the world，but people did not understand them．They did not know these changes were evidence(证据) of tiny plants and animals growing all around them.

    Thanks to software like Apple's Siri or Microsoft's Cortana, it's easier than ever to do something on our phone or computer. All we have to do is "talk", and our favorite song starts playing a few seconds later. But in the neat" future, asking our phone to play a song by using our voice will seem as old--fashioned. That's because US tech company Microsoft recently applied for a patent* for a "brain control interface"(BCI): meaning that soon, we may be able to control our phone and computer with our thoughts.

    BCI technology works by changing brain signals into computer commands. This technology isn't brand new, however. Last year, for example, it was reported that scientists were able to help a disabled man from the US, 53-year-old Bill Kochevar, to move again. To do this, Kochevar was fitted with BCI technology, as well as equipment to make his muscles move. After a few weeks of getting used to it, Kochevar was able to use his thoughts to "tell" the BCI to move his muscles, meaning he was able to feed himself for the first time in years.

    Apart from helping disabled people, it's hoped that BCI technology will improve the daily lives of other people too. US social networking platform Facebook announced last year that it was working off BCI technology to help people type by using their brain. By 2020, the company hopes to have created a system that will allow people to type up to 100 words per minute just by thinking about them.

    However, many people are worried that technology that tan read our thoughts will create privacy problems, especially if social media companies are included. But Facebook researcher Regina Dugan said at a meeting last year that the company has no interest in reading people's private thoughts. "That might be more than any of us care to "know. And it's not something any of us should have a right to know," she said.

    Albert Einstein is right once again! He thought of the idea about gravitational waves years ago with his Theory of Relativity, but scientists are finally discovering that it really exists now. But what are gravitational waves, and why are they important?

    Well, gravitational waves are made by black holes and can change time in space. Black holes aren't holes but are lots of matter put together into a very small area. They are created when a star, much like our sun, explodes and leaves behind this dense* material. It doesn't shine like a star any more, and it becomes black.

    The black holes that made these waves are special. About 1.3 billion years ago, there were two black holes that kept moving closer and closer together. Finally, they hit each other and formed one big black hole. The energy is given off and created the ripples* in space. These ripples are gravitational waves. For example, imagine you throw a stone into a pool. It creates ripples that change the shape of the water. Well, that's kind of what the influence of one black hole hitting the other has in space.

    Gravitational waves are hard to explore. But thanks to the efforts of scientists, the ripples were discovered on Feb. 11th, which is the first time in human history. Einstein was excellent to know this 100 years ago before we have the technology. It can give us a new view of the universe we live in. The discovery of gravitational waves, unlike stars, galaxies and other bright objects, black holes don't produce light, so we can't see them by tools. Gravitational waves allow scientists to look at the universe not only with light, but also with gravity. "Everything else in astronomy like the eye," A scientist told The New York Times. "Finally, astronomy grew ears. We had never ears before."

    Now, we will be able to find black holes and things that are much further away from Earth, which means much more space exploration in the future. And who knows, this discovery could even lead to time travel!