There are many colors in nature. But do you think that a color has weight? I think you'll say 6/no". But I'm afraid you are wrong. If you don't believe it, you may do a small experiment(实验).

  First, put two objects with the same weight into two boxes. Then cover the boxes.Third, wrap(包裹) one box with a red piece of paper, the other one with a white piece of paper. OK. Now hold the boxes with your hand one by one. It is certain that you will think the red one is a little heavier.

 Why do you think so? A scientist found that different colors have different weights in man's mind. That is to say, every color has its own weight in our mind.

 The scientist told us that colors also have smell. Can you smell the color? Of course not. Then why did the scientist say S07 That is because every color stands for (代表) a kind of light with a certain wavelength,(波长). It reaches our brain through sense organs

 According to this discovery, scientists say that people accept the colors they like, and refuse the colors they hate. So your body and mind will be healthy by using the colors you like. Or you'll be nervous or even get ill.  For example (例如) ,  you like blue and hate red.  If you stay in a room with red windows, wallpaper and furniture（家具) for two hours, you'll feel you have been there for four hours. But if the room is blue, you'll feel you have been there for only an hour.  And, if a person walks out of a blue room and into a red room, his temperature will rise.That means our body temperature will change with different colors.

    There are some very good inventions which， for one reason or another， don't become popular. These inventions should be better known， even though I think that some of them are crazy. Let's have a look at some of these inventions and see if you agree that they should be more successful.

    The Australians had a great idea to stop people from drinking and driving. The idea was that if a driver wanted to start the car， she or he would have to blow into a bag first. If there was too much alcohol(酒精) in their breath， the car wouldn't start. It sounded like a great idea to me， but people said that they might need to drive the car in an emergency even if they had drunk too much alcohol. Another idea I liked was an invention by a scientist who thought his children watched too much TV. He linked the TV to an exercise bike so that the electricity to power the TV was generated(产出) by the bike. If the children wanted to watch a lot of TV， they had to pedal(踩踏板) very hard. I found another invention on the Internet which was intended (倾向于) to encourage good habits. Believe it or not， this invention was an ashtray(烟灰缸) which spoke to you when you lit a cigarette! The “voice” of the ashtray was activated (启动) by the heat from the cigarette and reminded you how dangerous it is to smoke.

    One of the strangest inventions I have come across is a bicycle which can cross rivers! The idea was that when you came to a river， you could inflate a huge plastic ball all around the bike. You would then get into the ball which would float on the river while you pedaled the bike inside the ball! Why not use a bridge instead? A friend of mine at school once bought a strange pair of football shoes. On the bottom of the shoes there was a rotating pad of studs (转动钉垫). The idea was that you would change direction more quickly if the studs rotated with you. The problem was that every time you stopped you changed direction whether you wanted to or not! I think he wore those shoes twice! One thing I would like is a baseball cap with a built-in radio so you can listen to sport all day with your hands free. While we are on the subject of sport， the Americans invented a kind of robot for sports fans. If you were watching your team on TV on your own， you could press a button and the robot would do “high fives” with you! Fantastic! I wonder if you have any good ideas for inventions like these.

    Teenagers are known for being creative and full of new ideas. Let's have a look at these teenage inventions that might change the world.

    No Car Day first started by 34 cities in France on September 22, 1998. People started it to protect the environment. By now, more than 1,000 cities around the world have a No Car Day.

    The first No Car Day in China was in Chengdu in 2001. Other cities, including Taipei, Shanghai and Wuhan, also support(支持) the day.

    In Beijing, more and more people are joining in the program. It asks drivers to leave their cars at home for one day each month and walk or ride a bike to work. It also calls on Beijingers not to use cars on June 5(World Environment Day). The slogan(口号) for the day is, "If we drive for one less day, we can have one more nice day."

    So far, more than 200,000 drivers Show their support. "We can't decide the weather, but we can choose not to drive," said Wu Zhonghua, a car dub manager. Beijing is trying to have 238 blue sky days this year. In the first quarter of 2017, Beijing only had 52 blue sky days. This was 11 days less than the number for the same period the year before.

    We must do more for No Car Day.

    Big data (数据) is a lot of sets of information that are put together so they can be used by a computer program. The computer program looks for different kinds of answers or patterns in the data. Big data can have different kinds of information from many sources, such as information that comes from schools, social media sites, companies, and governments. One set of data can have people's names and addresses. Another set can have what they like, where they go to school, and how much time they spend on the computer.

    Big data can be used in many ways. The government uses it to understand how many people travel on buses or trains. This information is then used to make bus or train systems better. Some schools use big data to understand which children may need extra help in class. The teacher can then give certain students more help or support so those students can succeed in school. Companies use big data, too. It helps them understand who buys their products. For example, one company uses weather data to see when people eat the most ice cream.

    Big data can be used for good reasons. Some hospitals use big data to predict if a baby who is born too early will get sick. The hospital can then take extra steps to take care of that baby so he or she does not get sick. Big data can also be used for bad reasons. It can be used to predict which kinds of people are likely to break the law or hurt others, even if they have not done anything wrong.

    How can big data be used for good and bad things? It is because the computer programs used to look at big data and understand it are written by people. People think a certain way. Because they think a certain way, they build a model of those ideas. These ideas are then used to look at the data. Sometimes, these ideas are helpful for people or businesses. Other times, bad ideas can cause problems for certain groups of people.