You can tell a lot about people by looking at their hair – not just whether they brush, spray or blow-dry. Scientists have found a way to use hair to figure out where a person is from and where that person has been. The finding could help solve crimes, among other useful applications.

    Water is central to the new technique. The liquid makes up more than half an adult human's body weight. Our bodies break water down into hydrogen(氢) and oxygen. Atoms of these two elements end up in our tissues, fingernails, and hair.

    But not all water is the same. Hydrogen and oxygen atoms can vary in how much they weigh. In the case of hydrogen, for example, there are three types according to their weights. Each type is called a hydrogen isotope（同位素）. And depending on where you live, tap water contains different isotopes.

    Can hair record this information? That's what James R. Ehleringer, an environmental chemist at the University of Utah, wondered. To find it out, he and his colleagues collected hair from hair stylists in 65 cities across the United States. Even though people drink a lot of bottled water these days, the researchers have found that people's hair has the same isotopes as found in local tap water. That's probably because people usually cook their food with the local water.

    Authorities can now use the information to analyze hair samples from criminals or crime victims and narrow their search for clues. For example, one hair sample used in Ehleringer's study came from a man who had moved from San Francisco to Salt Lake City. As his hair grew, it reflected his change in location.

The idea of being able to walk on water has long interested humans greatly. Sadly, biological facts prevent us ever accomplishing such a thing without artificial aid—we simply weigh too much, and all our mass pushes down through our relatively small feet, resulting in a lot of pressure that makes us sink.

    However, several types of animals can walk on water. One of the most interesting is the common basilisk Basilicus basilicus, a lizard (蜥蜴)native to Central and South America. It can run across water for a distance of several meters, avoiding getting wet by rapidly hitting the water's surface with its feet. The lizard will take as many as 20 steps per second to keep moving forward. For humans to do this, we，d need huge feet that we could bring up to our ears in order to create adequate w hitting. ''

    But fortunately there is an alternative : cornflour. By adding enough of this common thickening agent to water (and it does take a lot), you can create a “non-Newtonian” liquid that doesn't behave like normal water. Now, if the surface of the water is hit hard enough, particles(粒子）in the water group together for a moment to make the surface hard. Move quickly enough and put enough force into each step, and you really can walk across the surface of an adequately thick Liquid of cornflour.

    Fun though all this may sound, it's still rather messy and better read about in theory than carried out in practice. If you must do it, then keep the water wings handy in case you start to sink--and take a shower afterward!

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    If you are a fruit grower—or would like to become one—take advantage of Apple Day to see what's around. It's called Apple Day but in practice it's more like Apple Month. The day itself is on October 21, but since it has caught on, events now spread out over most of October around Britain.

    Visiting an apple event is a good chance to see, and often taste，a wide variety of apples. To people who are used to the limited choice of apples such as Golden Delicious and Royal Gala in supermarkets, it can be quite an eye opener to see the range of classical apples still in existence, such as Decio which was grown by the Romans. Although it doesn't taste of anything special，it's still worth a try，as is the knobbly(多疙瘩的) Cat's Head which is more of a curiosity than anything else.

    There are also varieties developed to suit specific local conditions. One of the very best varieties for eating quality is Orleans Reinette, but you'll need a warm, sheltered place with perfect soil to grow it, so it's a pipe dream for most apple lovers who fall for it.

    At the events, you can meet expert growers and discuss which ones will best suit your conditions, and because these are family affairs, children are well catered for with apple­themed fun and games.

    Apple Days are being held at all sorts of places with an interest in fruit, including stately gardens and commercial orchards(果园)．If you want to have a real orchard experience, try visiting the National Fruit Collection at Brogdale，near Faversham in Kent.

    Early people lived by hunting animals and gathering grains. After a tribe(部落） had lived in an area for some time, its food supply would begin to reduce. Then the tribe had to move to new hunting grounds where there was more food.

    This way of life caused special problems for the tribes. They were forced to depend on luck, as well as on their hunting skills. If they could find no game, the whole tribe was in danger of starving. And when the hunters had good luck one day, they were not sure to find game the next time. The tribes moves often because much land was needed to support their people.

    Finally, people learned that they could grow their food. At first, the women of tribes raised patches of wild grain. Later, people discovered that they could plant their own seeds. Farming slowly became a way of life.

    As people turned away from hunting to farming, their life changed. When the food supply became more constant, they no longer moved from place to place. The success of their crops depended partly on the weather, but there were also things they could do to help crops grow.

    In the past, a tribe had to travel many miles for food. Now , only a small amount of land was necessary to feed the whole tribe. The tribe could grow in size because farming provided a way to feed people.

    In beautiful rural Montana lies the town of Livingston. Around half the students in the Livingston School District qualify for free or reduced-price lunches, according to local educator Rachael Jones, known as "Farmer Jones". She is the director of the Livingston Farm to School program, which uses the district's two greenhouses and four gardens to grow food that supplements school meals while offering kids hands-on lessons. Jones said, "In many places around the country, if you can't pay for your school meal, you don't eat. Well, here, we don't turn anyone away."

    The town's school district and community members started the program eight years ago. It's part of the National Farm to School Network, which aims to increase access to local food and nutrition education across the country. Jones, who attended public school in Livingston as a kid, has headed up the local program since 2014. Farm to School enriches curriculums in all of the schools through garden lessons, cafeteria and kitchen lessons, and classroom lessons.

    Research has shown that healthy school meals can enhance academic performance, including improved test scores. Though the Farm to School program is not aimed solely at lower-income students, Jones said, "Such kids are more likely to eat lunch provided by the school. Eventually she wants to get healthy, affordable meals on the plate of every child in Livingston.

    It is important for kids to understand where their food comes from. That's a life changing experience for them. Jones said," When I grew up a big force in my life was my grandma Ethel. She taught me from a really early age the value of growing my own food. I worked in her gardens with her and somehow, through all of those experiences —eating her tomatoes and canning pickles with her —it really built up my trust and knowledge in food systems. I'm so thankful for her!"

On the day the tornado hit, there was no indication severe weather was on its way—the sky was blue and the sun had been out. The first alert my husband, Jimmy, 67, and I, 65, got came around 9 p. m. , from some scrolling text on the TV Jimmy was watching. He ran upstairs to find me in our third-floor bedroom, and we changed the channel from the presidential primary debate I had been watching to our local Pensacola, Florida, station.

No sooner had we found coverage of the tornado than it was on top of us. It was the loudest thing I have ever heard. The bones of the house shook, and the power went out. Pink insulation flew into the room from a trapdoor to the attic, and the wind began to roar through the house.

I didn't know how or if we would make it down the steps. It felt as if there were no floor underneath me as the wind lifted me off my feet. I gripped the banister (栏杆) and tried to move forward, but this intense pressure held me in place.

By the time I reached the closet, the tornado had been over us for about a minute. Jimmy pushed me down to the closet floor, but he couldn't get inside himself because of the wind. I gripped Jimmy's arm. My knees and scalp were full of glass, but in that moment, I felt no pain.

All of a sudden, Jimmy lifted off his feet like people in tornadoes do in the movies. I thought he was gone. And then everything stopped. He landed on his feet. In those first quiet moments, I couldn't believe it was over. Jimmy said he'd go outside to check. "No," I said. "Don't leave me. "

Our neighbor says the storm lasted four minutes. In that time, four of the twelve town houses in our unit were completely destroyed. Of the houses left standing, ours suffered the most damage. Amazingly, none of us were severely injured.