People who do not get enough vitamin A in their diet may develop night blindness. But in the developing world, a lack of vitamin A causes much more serious harm to children. The world Health Organization links the lack of vitamin A to as many as 250,000 child deaths every year.

    One excellent source of vitamin A is found in newly developed sweet potatoes with orange flesh. Orange sweet potatoes contain high levels of beta-carotene, which the body changes into vitamin A. Experts say orange sweet potatoes could help the Africans who are lacking in vitamin A. But, first, more people will need to be persuaded to eat them. Sweet potatoes need a better image in Africa. Jan Low with the International Potato Center says, “We do have an image problem with sweet potatoes. In many African countries, they are seen as a crop of the poor.”

    Ms. Low explains that sweet potatoes are mainly grown by poor women to feed their families in case another crop fails. The sweet potatoes commonly grown in Africa have white or yellow flesh. But they are low in vitamin A.

    Jan Low took part in a project to study how to market orange sweet potatoes to Africans best. She worked on an information campaign(活动) in Mozambique and Uganda. The campaign included radio messages about the nutritional(营养的) benefits of the orange sweet potato. They advertised its ability to “fight diseases, make you strong, clear you skin and make you look healthy”. In areas without radio, the campaigners spread the message through theater. The performances included singing, dancing and storytelling. And everywhere they went, the campaigners wore orange T-shirts and hats. They even drove orange cars.

    Dan Gustafson heads the Washington office of the United Nations Food and Agriculture Organization. He mentions the efforts in the past to increase the popularity of other nutritious crops. He says most of these efforts failed because organizers of the campaigns did not consider what people wanted to eat. People want to eat what they are familiar with. But Mr. Gustafson sees a better chance for the efforts to increase the popularity of the orange sweet potato in Africa. Except for the color, the orange sweet potato is almost the same as what people already eat. Dan Gustafson says, “I think this time the campaigners will succeed, because they have made enough advertisements and the difference between the vegetable they have advertised and what people already eat is not a radical one.”

    For twenty years, I saved all my college course notes and textbooks: that's a lot of paper.  Worse, it wasn't easy to carry them around—and trust me, they weren't light — on at least seven moves. Yet I never once looked at them. They sat in our basement, covered in a thick layer of dust. If books and papers could wonder, they'd wonder why they were still under our stairs after all those years. What were my plans for them? When would the Big Day come?

    Well, the Big Day eventually did arrive; only it was different than expected. My wife, always more accepting changes than I am, finally convinced me to clear out the entire mess.

    The pain I experienced was also unexpected. I didn't feel nostalgia(怀旧的), or suffer pains for long-lost magical moments of my education. No, what hurt me was to come across those terrible papers I'd written, reminders of poor study habits, immaturity(不成熟), and an embarrassing lack of comprehension. It was great to get rid of them. I won't have to carry those dusty, filthy(脏兮兮的) things on our next move. But it was also a clearing of personal history. Initially, I struggled with this. My books, my notes, and my papers were primary source materials, documenting an important time in my life. To clear them out was to clear out the truth. What I've learned since taking this leap is that the lesson is more important than the truth. I feel as if much of my real education during my college years isn't in the documents but now in me. So I am glad to free myself of this physical burden of carrying them around. And what's better is that I don't need to look back on those painful moments. They belong to the past.

    You might want to consider doing something similar, either under the stairs of your basement or in your mind. Not so long ago, a very smart person created a new holiday—Discardia!—to be celebrated four times a year. It's a great idea, and every time I clear things out, I feel better physically and psychologically. Discardia's slogan is “Let go of everything that doesn't make your life awesome!” What is the personal rubbish piling in your life? Clear it out and make your life awesome.

    When my daughter Sara was in the fifth grade, she came to me with a problem. "Marcy hates me!" she cried. "Because Kathy is my friend, too. She wants me to be her friend and nobody else's. You talk to Marcy. You tell her that I want to be her friend, but I can have other friends, too!"

    Oh! I looked at her for a few moments, wondering how I got into this mess (困境), when suddenly an idea came to me.

    Picking up two baskets from the living room, I explained, "When everyone is born, he or she has a little basket. This little one here is yours. The big one is mine. As you grow, so does the basket. You can see your little basket is inside mine because when you were born, there were too many things you couldn't do for yourself. I did everything you couldn't do on your own."

    She nodded.

    "Well, as you grew older and began to do some things on your own, I began placing a few more things in your basket. When you learned to tie your shoes, that went in your basket."

    She said softly, "I can tie my own shoes."

    "Right. As you grow older, there will be more and more things you must do on your own." As I spoke, I gradually took her basket out of mine and handed it to her. "You will finally carry your own basket with things only you can do."

    She looked up at me and said, "I understand. There are some things that I have to do for myself because they are in my basket."

    What happens inside the head of a soccer player who repeatedly heads a soccer ball. That question motivated a study of the brains of experienced players.

    Researchers at the Albert Einstein College of Medicine in New York selected 34 adults, men and women. All of the volunteers had played soccer since childhood and  now competed year﹣round in adult soccer leagues. Each filled out a detailed questionnaire developed especially for this study to determine how many times they had headed a soccer ball in the previous year, as well as whether they had experienced any known concussions in the past.

    Then the players completed computerized tests of their memory and other learning skills and had their brains scanned. using a complex new M.R.I. technique which can find structural changes in the brain that can't be seen during most scans.

    According to the data they presented, the researchers found that the  players who had headed the ball more than about 1, 100 times in the previous 12 months showed significant loss of white matter in parts of their brains involved with memory, attention and the processing of visual information, compared with players who had headed the ball less.

    This pattern of white matter loss is "similar to those seen in traumatic brain injury", like that after a serious concussion, the researchers reported, even though only one of these players was reported to have ever experienced a concussion.

    The players who had headed the ball about 1, 100 times or more in the past year were also generally worse at remembering lists of words read to them, forgetting the words far more often than players who had headed the ball less.

    The European Union(EU) is an organization of European countries. The countries are independent and are governed in different ways. In the United Kingdom, for example, the head of state is a king or queen. In France, on the other hand, the head of state is a president. But each of them sends representatives(代表)to European Parliament, which has some control over what happens in each of the member countries.

    The idea of the EU began in the 1950s. The first members were France, Germany, Belgium, Luxembourg, the Netherlands and Italy. Little by little, the number increased during second half of the twentieth century. By the year 2000, there were 15 member countries. The new countries were Austria, Denmark, Finland, Greece, Ireland, Portugal, Spain, Sweden and the United Kingdom.

    In 2004, the EU increased to 25 members. The Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, the Slovak Republic and Slovenia, plus the Mediterranean islands of Cyprus and Malta all became members. The expanded EU has a population of more than half a billion people, twice as big as the population of the US.

Discovering the beauty of the science and maths that shape our everyday lives, an experience in Wonderlab will fuel your imagination and inspire you to see the world around you in new and exciting ways. Come and enjoy yourself!

What to see

Spread across seven different zones, there're loads of opportunities to get hands on with real scientific phenomena. Observe live experiments at our Chemistry Bar, see lightning strike before your eyes, play with forces on giant slides or travel through space under a canopy (苍穹)of stars. You can also take part in explosive science demonstrations led by our talented team of explainers. With 50 mind-blowing wonders of science to enjoy, Wonderlab is an experience unlike any other. Besides, a selection of shows will be performed daily in Wonderlab's beautiful new show space. They are free of charge and last 20 minutes.

Tickets

♦ Day pass:  £ 6 per person.

This ticket gives you day-long access to Wonderlab, perfect whether you're planning a special trip to the Museum or simply passing through London and want to feed your curiosity.

♦ Annual pass:  £ 10 per person.

For less than the price of two visits, give yourself a year packed full of wonder, curiosity and breathtaking experiences.

Opening times

Open seven days a week, 10:00 — 18:00 (last entry 17:15). Wonderlab will be closed on December 24，25 and 26 and will be open as usual from December 27.

During school holidays our opening hours are 10:00 — 19:00 (last entry 18:15). Please note that in peak periods (from midday onwards) we are experiencing long queues due to the gallery's popularity.