Polar bears are one of the most popular animals for people. Polar bears are different from every other bear in the world. This is because polar bears have white fur. However, there are many facts about polar bears that people might not be aware of .

    The skin of polar bears is black, which according to thinkquest.org allows them to absorb more heat from the sun. Polar bear fur is transparent , because it is made up of hollow guard hairs. Loc.gov explains that the reason polar bears display white fur is that when the sun hits the fur ,the hollow spaces in the hair scatter the light. Since none of the light is absorbed, the light reflected back appears white to human eyes.

    Polar bears' conservation status is considered close to extinction. Global warming is considered the main cause of the decline in polar population. Polar bears use ice floats to hunt for their food. However, these ice floats are melting so polar bears are starting to drown in the search for food, and the food is becoming more difficult to get. Contrary to popular belief, polar bears do not eat penguins, because polar bears are not found in the Antarctic region of the world. Polar bears are only found around the Arctic Circle. Polar bears do not drink water. They get all the water they need from the prey they eat.

    FES. Gov specifies that polar bears are considered the largest land carnivores(食肉动物) in the world. The polar bear weight ranges between 700--1,500 pounds. Since the polar bear habitat is melting away, their main evolutionary advantages are fading. Polar bears are not able to use their camouflage(伪装) to find prey in habitats not covered with snow. Polar bears do not hibernate(冬眠). However, when the weather gets uncomfortable, or mothers give birth, polar bears will dig themselves a hidden home.

    What can we do to help save the polar bears? We can donate to organizations like the World Wildlife Fund, reduce our carbon footprint, and send letters to politicians explaining to them that we need to set up more preserves to help save the polar bear habitat.

    A spaceship is flying to the sun in summer 2018! It will be the first-ever to a star and will be one of the biggest achievements space exploration (探险) in human history. The purpose is to study the sun's outer atmosphere and better understand how stars work.

The spaceship, with no man inside, will fly within 4 million miles of the sun's surface - right into the solar atmosphere, where the temperature is over 4,500℃. To protect the spaceship, it is covered with a 12cm-thick coating.

    The spaceship is called Parker Solar Probe and it is named after Eugene Parker, a professor from the University of Chicago. It's the first NASA spaceship to be named after a researcher who is still alive. In 1958, Eugene Parker first created the term “solar wind”-the sun sending out a flow of particles (颗粒) and energy.

    “The spaceship is going where it has never been before. It's very exciting that we'll finally get to know more about the solar wind. I'm sure there will be some surprises. There always are,” said Professor Parker.

    Parker calls it a heroic scientific space adventure, and he means that the spaceship will have to experience high temperatures and sun radiation (辐射). “The spaceship is going to do the hottest and fastest work. I love to call it the coolest hottest work under the sun,” said Scientist Fox Nasa.

    According to a new US study, couples who expect their children to help care for them in old age should hope they have daughters because they are likely to be twice as attentive overall.

    The research by Angelina Grigoryeva, a sociologist at Princeton University, found that, while women provide as much care for their elderly parents as they can manage, men do as little as they can get away with and often leave it to female family members.Her analysis of the family networks of 26,000 older Americans concluded that gender(性别) is the most important predictor(预示物) of whether or not people will actively care for elderly parents.

    In a paper being presented at the annual conference of the American Sociological Association in San Francisco, she concludes that simply having a sister makes men statistically likely provide less care.

    Using data from the University of Michigan Health and Retirement Study, a study which has been tracking a cross-section of over-50s for the last decade, she calculated that women provide an average of 12.3 hours a month of care for elderly parents while men offer only 5.6 hours.

    “Whereas the amount of elderly parent care daughters provide is associated with limitations they face, such as employment or childcare, sons' caregiving is associated only with the presence or absence of other helpers, such as sisters or a parent's spouse(配偶),” she explained.

    “Sons reduce their relative caregiving efforts when they have a sister, while daughters increase theirs when they have a brother.”

    “This suggests that sons pass on parent caregiving responsibilities to their sisters.”

    In the UK, the 2011 census(人口普查) showed that there are now around 6.5 million people with caring responsibilities – a figure which has risen by a tenth in a decade.

    But many are doing so at the risk of their own health. The census showed that those who provide 50 hours or more of care a week while trying to hold down a full- time job are three times more likely to be struggling with ill health than their working counterparts(相对应的人) who are not carers.

    Will it matter if you don't take your breakfast? Recently a test was given in the United States. Those tested included people of different ages, from 12 to 83. During the experiment, these people were given all kinds of breakfasts, and sometimes they got no breakfast at all. Special tests were set up to see how well their bodies worked when they had eaten a certain kind of breakfast. The results show that if a person eats a proper breakfast, he or she will work with better effect than if he or she has no breakfast. This fact appears to be especially true if a person works with his brains. If a student eats fruit, eggs, bread and milk before going to school, he will learn more quickly and listen with more attention to class.

    Opposite to what many people believe, if you don't eat breakfast, you will not lose weight. This is because people become so hungry at noon that they eat too much for lunch, and end up gaining weight instead of losing. You will probably lose more weight if you reduce your other meals.

    Heat has been used to control hair for hundreds of years. But how much is too much? If you have ever opened a very hot oven, you know that heat can burn your eyebrows off your face very quickly. A scientist from Purdue University in Indiana is trying to find a scientific answer on how hot is too hot when it comes to your hair.

    Many women and some men are very particular about their hair. Some people who have naturally curly hair prefer to have it straightened. Others with straight hair want to have curls. Tahira Reid is one of those people. As an African-American woman, she is familiar with the challenges of maintaining (保养)curly hair.

    Tahira Reid and other researchers at Purdue University are studying how heat treatment interacts with different types of hair and how to prevent damage. Amy Marconnet is an assistant professor. She says the team is seeing how heat and temperature relate to their research.

    In a Purdue University's lab, team members designed a hair straightener tool —a flat iron with temperature control. They attached it to a robotic arm that moved over pieces of hair. They controlled the temperature while the device straightened hair.

    What did they find? Their study found that the heat weakens or breaks a protein called keratin, responsible for the hair's shape, and temporarily changes it. But nobody knows exactly what level can make the heat actually cause forever change. Researchers say early results are a bit inconclusive.

    It turns out that everyone's hair is different and there's no exact temperature where hair straightening becomes hair damage. Ms Reid says they will continue their research in the hope of finding what works best without damaging hair.

Many scientists today are convinced that life exists elsewhere in the universe—life probably much like that on our own planet. They reason in the following way.

    As far as astronomers can determine, the entire universe is built of the same matter. They have no reason to doubt that matter obeys the same laws in every part of the universe. Therefore, it is reasonable to guess that other stars, with their own planets, were born in the same way as our own solar system. What we know of life on earth suggests that life will arise wherever the proper conditions exist.

    Life requires the right amount and kind of atmosphere. This eliminates(除去) all those planets in the universe that are not about the same size and weight as the earth. A smaller planet would lose its atmosphere; a larger one would hold too much of it.

    Life also requires a steady supply of heat and light. This eliminates double stars, or stars that flare up suddenly. Only single stars that are steady sources of heat and light like our sun would qualify.

    Finally, life could evolve(进化) only if the planet is just the right distance from its sun. With a weaker sun than our own, the planet would have to be closer to it. With a stronger sun, it would have to be farther away.

    If we suppose that every star in the universe has a family of planets, then how many planets might support life? First, eliminate those stars that are not like our sun. Next eliminate most of their planets; they are either too far from or too close to their suns. Then eliminate all those planets which are not the same size and weight as the earth. Finally, remember that the proper conditions do not necessarily mean that life actually does exist on a planet. It may not have begun yet, or it may have already died out.

    This process of elimination seems to leave very few planets on which earthlike life might be found. However, even if life could exist on only one planet in a million, there are so many billions of planets that this would still leave a vast number on which life could exist.