This Monday, the nation will start to celebrate Presidents' Day, just seven days before George Washington's birthday. Everyone agrees that day is a holiday. but is it just to celebrate George Washington's Birthday? What about Abraham Lincoln? Some government offices call it Presidents' Day. Others say the holiday is officially Washington's Birthday. Confused yet?

    George Washington was elected the country's first President on April 30,1789. Soon after, Americans began publicly celebrating his birthday. Presidential historians say the actual date of George Washington's birth is February 11,1732. But a change inthe calendar system 20 years later shifted all dates, making Washington's birthday February 22, which is now well accepted. In 1879. Congress made Washington's birthday an official federal holiday. It was the first federal holiday to celebrate an individual's birthday. In 1968, Congress passed the Monday Holidays Act, which moved the holiday to the third Monday in February. The new law did not change the holiday's name. It was still called Washington's Birthday, even though some law makers wanted to call it Presidents' Day to include Abraham Lincoln, whose actual birthday is February 12.

    Many people argue that the holiday should celebrate all past Presidents. They feel Lincoln should be honored for his role in preserving the nation during the Civil War and helping to free slaves. Others feelthe holiday should only honor Washington. the country's first President. They say shifting the focus away from Washington would mean future generations of kids would not know about the Father of Our Country.

    Laws have been introduced in Congress over the years to requireuse of the term “George Washington's Birthday.”but none of those laws have been passed. Meanwhile, many stategovernments and school districts now use the term “Presidents' Day．”Many stoles also use it to promote holiday sales.

    Should the holiday honor Washington, Washington and Lincoln, or all past Presidents? Write to emailbag@timeforkids, com and tell us what you think.

    The wonderful experiment I am going to introduce proves that air is just all around and that it presses down upon us. Air pressure is a wonderful force. When you swim underwater, you can feel water push down your body. The air all around you does the same. However, your body is so used to it that you do not notice this. The pressure is caused by a layer of air called the atmosphere. This layer surrounds the Earth, extending to about five kilometers above the Earth's surface.

    The following experiment is an easy one that you can do at home. But make sure that you are supervised, because you will need to use matches. Now for the experiment！

    What you need:

·A hard-boiled egg without the shell

·A bottle with a neck slightly smaller than the egg

·A piece of paper

·A match

Method:

1） Check that the paper will sit firmly on the neck of the bottle.

2） Tear the paper into strips and put the strips into the bottle.

3） Light the paper by dropping a burning match into the bottle.

4）Quickly sit the egg on the neck of the bottle.

Result:

    Astonishingly, the egg will be sucked into the bottle. Your friends will be amazed when you show them the experiment. But be careful when you handle matches.

    Why it happened

    As the paper burns, it needs oxygen and uses up the oxygen（air）in the bottle. The egg acts as a seal in the neck of the bottle, so no more air can get inside. This reduces the air pressure inside the bottle. The air pressure must equalize, so more air from outside must enter the bottle. The outside air pressure against the egg and then the egg is pushed into the bottle! This proves that air is all around and that it is pressing down on it.

    It was dawn of March 21, 2018. Gary Messina was on his morning run along New York City'8East River. Suddenly something caught his eye—a large 60-year-old man balancing on the four-foot-high fence that guarded the path from the water. As Messina got closer to the scene, the man took a step forward and slipped into the dark river below.

    When Messina reached nearer, the man was struggling in the water, clearly unable to swim. Other joggers also heard the man's cry. David Blauzvern and John Green dropped their phones and keys on land and jumped in. “ People had called the police, but it was unclear when they'd get there,” says Green. “We just reacted. Messina joined them in the river. Just as the jumper was losing strength, Blauzvern take hold of him. The pair were about 30 yards from the seawall when Messina and Green caught up to them. They seized the man, with Blauzvern supporting his back and Messina and Green holding him up from either side. As the men made their way toward the concrete seawall that stretched for blocks in each direction, Blauzvern had an awful realization:there was no way out of the river.

    By now, a crowd had gathered on land. “A rescue boat is on its way, someone yelled to them. Swimming forward was getting tougher by the minute. The jumper, who was six foot two and weighed around 260 pounds, was heavy in his rescuers' arms. After ten minutes, they managed to get to the river's edge. “I've never been so out of breath, ”says Blauzvern.

    Fifteen minutes after the men had jumped into the river, the two-man rescue boat appeared. But because it couldn't risk getting too close to the seawall, the men had to swim out to it. “I was completely out of energy at this point, “says Blauzver. The men in the water pushed the jumper while the men in the boat pulled him up and, finally, to safety. The man they had saved was taken to the hospital for evaluation(评估). Details on his condition have not been released. As for the rescuers, each of them was at work by 10:30a. m. “I was a bit late,” admits Blauzvern, smiling. “But I had a good excuse.”

    How much weight a baby gains during its first month could determine its IQ, new research found. The study found that children who gain more weight, and whose heads grow quickly during the first month of life, tend to have a higher IQ when they start school.

    Researchers at the University of Adelaide, in Australia studied 13, 800 children who were born at full-term. They found that those who put on 40% of their birth weight in the first four weeks had an IQ 1.5 points higher than those who only put on 15% of their birth weight. Those who experienced the biggest growth in head circumference(头围) also had the highest IQs by the age of six.

    "Head circumference is an indicator of brain volume, so a greater increase in head circumference in a newly-born baby suggests more rapid brain growth, "says the author of the study, Dr. Lisa Smithers. She added, "Overall, newly-born children who grew faster in the first four weeks had higher IQ scores later in life. Those children who gained the most weight scored especially high on the verbal IQ at age 6. This may be because neural (神经的) structures for the verbal IQ develop earlier in life, which means the rapid weight gain during the first month could be having a direct cognitive benefit for the children."

    Previous studies have shown the association between early postnatal (产后的) diet and the IQ, but this is the first study of its kind to focus on the IQ benefits of rapid weight gain in the first month of life. Dr. Lisa Smithers says the study further highlights the need for successful feeding of newly-born babies." We know that many mothers have difficulty establishing breastfeeding in the first week of their babies' life,” Dr. Lisa Smithers said.

    "The findings of our study suggest that if babies are having feeding problems, there needs to be early intervention(干预) in the management of that feeding."

    Going to university is supposed to be a mind-broadening experience.

    That assumption is possibly made in contrast to training for work straight after school. But is it actually true? Jessika Golle of the University of Tubingen, Germany, thought she would try to find out.

    Her result, however, is not quite what might be expected. It shows that those who have been to university do indeed seem to leave with broader and more inquiring minds than those who have spent their immediate post-school years in vocational training for work. However, it is not the case that university broadens minds. Rather, work seems to narrow them.

    After studying the early career of 2095 German youngsters, Dr. Golle reached the conclusion.

    During the period under investigation, Germany had three tracks in its schools: a low one for pupils who would most probably leave school early and enter vocational training; a high one for those almost certain to enter university; and an intermediate one, from which there was a choice between the academic and vocational routes.

    The team used two standardized tests to assess their volunteers. One was of personality traits and the other of attitudes. They administered both tests twice once towards the end of each volunteer's time at school, and then again six years later.

    Of the original group, 382 were on the intermediate track, and it was on these that the researchers focused. Of them, 212 went to university and the remaining 170 chosen for vocational training and a job.

    When it came to the second round of tests, Dr Golle found that the personalities of those who had gone to university had not apparently changed. Those who had undergone vocational training and then got jobs were not that much changed in personality, either except in one crucial respect they had become more responsible.

    That sounds like a good thing, compared with the common public image of undergraduates as a bunch of pampered layabouts(娇生惯养的闲人). But changes in attitude the researchers recorded were more worrying. In the university group, again, none were detectable. But those who had chosen the vocational route showed marked drops in interest in tasks that are investigative and enterprising in nature.

    And that might restrict their choice of careers. Some investigative and enterprising jobs, such as scientific research, are, indeed off limits to the degreeless.

    But many, particularly in Germany, with its tradition of vocational training, are not. The researchers mention, for example, computer programmers, finance-sector workers and entrepreneurs as careers requiring these attributes.

    If Dr Golle is correct, and changes in attitude brought about by the very training Germany prides itself on are narrowing people's choices, that is indeed a matter of concern.

    Many people, both men and women in the world love drinking. The popular wisdom for years has been that drinking in moderation (适度) —that's one “standard” drink a day for women and two for men—is linked to a lower risk of cardiovascular (心血管的) disease. But recent studies are casting some doubt on that long-held learning. Science now says it depends on your age and drinking habits.

    A 2017 study of nearly 2 million British with no cardiovascular risk found that there was still a modest benefit in moderate drinking, especially for women over 55 who drank five drinks a week. Why that age? Alcohol can influence the substance in the blood in positive ways, experts say, and that's about the age when heart problems begin to occur.

    Also, a 2018 study found that drinking more than 100 grams of alcohol per week—equal to roughly seven standard drinks in the United States or five to six glasses of wine in the UK—surely increases your risk of death from all causes and in turn lowers your life expectancy. Links were found with different forms of cardiovascular disease, with people who drank more than 100 grams per week having a higher risk of stroke, heart failure.

    Another 2018 study found that consistently drinking moderately, within the recommended amount of alcohol, had a protective effect on the heart over time. Unstable drinking habits were associated with a higher risk of heart disease, which the authors reflected might indicate broader lifestyle changes, such as poor health or stress. Former drinkers were also at greater risk.

    Overall, however, the latest thinking is that any heart benefit may be outweighed by other health risks, such as high blood pressure, certain cancers and liver damage.

    Women who drink are at a higher risk for breast cancer; alcohol contributes about 6% of the overall risk, possibly because it raises certain dangerous hormones in the blood. Drinking can also increase the chance you might develop liver, mouth and oral cancers. One potential reason： Alcohol weakens our immune systems, making us more likely to inflame (发炎)—a driving force behind cancer.