4hw.org: Recently, a primary school student's summer homework topic micro blog triggered a heated discussion. It is reported that there is a topic in the summer homework of grade one in Shanghai: let primary school students draw down the appearance of the moon at 7-9 every night for 28 days. Listen to is no problem, this problem can be difficult for scientists, because at night 7:00 to 9:00 on any corner of the earth can not see the moon!
July 31 reported, "from now on, please observe the moon once every night between 7:00 and 9:00, draw down the shape of the moon you see, and stick to it for 28 days. 'this is an assignment of "summer vacation life" for the first grade of Shanghai primary school. Does it look simple and interesting?
However, the subject baffled Tang Haiming, Secretary General of Shanghai Astronomical Society and senior director of Science Communication Studio of Shanghai Observatory, Chinese Academy of Sciences. It turns out that according to astronomical laws, the moon rises about 50 minutes later every day than the previous day. That is to say, about half of the time of each month, the moon does not rise until the next morning or even early in the morning, and then falls quietly in the daytime The child was unable to find the moon between 7 and 9 p.m. as required by the topic.
"To cultivate the scientific spirit of children, it is necessary for the examinees to be rigorous and meticulous in every detail. 'Tommy Hemingway called.
The moon will rise during the day
Turn to "summer vacation life", the reporter saw that the topic added, "if it rained or cloudy that day, you can not see the moon, you can first empty that day without painting. After 28 days, please guess, if you can see the moon in the empty days without drawing, what shape might the moon be? Fill in the moon shape you guessed, and make a mark below. '
Such statements can easily be misleading, he cautions. If the child thinks he can't see the moon, it's just because of the rain or cloudy weather, it's wrong. In fact, there is a period of time in every month, from 7:00 to 9:00 p.m., when the moon can't be seen anywhere on the earth Since the rising time of the moon is delayed for about 50 minutes every day, take Shanghai in July this year as an example. Since July 12, the rising time of the moon will be after 21:00, including 21:04 on July 12, 7:32 on the next day; 21:42 on July 13, 8:28 on the next day; 22:19 on July 14, the month The setting time is 9:26 the next day & hellip; & hellip; and so on. Until July 23, the rising time and the setting time of the moon are 4:36 a.m. and 18:43 a.m., respectively. Only when the visibility is high, can people catch a glimpse of the moon that is going to 'go home' with the sun at the same time.
No loopholes in scientific work
'if the child really wants to complete the moon phase map according to his own observation, I'm afraid he can only stay up late. 'said tohemingway with a smile. He admits that it's not hard to 'guess' the moon's phase with search engines or nature textbooks. But the important thing of scientific inquiry is not the result but the process, so as to guide children to grasp the method of seeking truth from facts There are loopholes in scientific knowledge in scientific homework, which is inevitable to be regretted. He suggested adding a small question to the assignment would be very interesting. 'when you don't see the moon in the sky from 7:00 to 9:00 in the evening, think about what's the reason?' in this way, you can also let the child look up at the stars at fixed points at a fixed time, make records and observations, rather than imagine from the sky.
Tang Haiming said that if this common sense loophole is not noticed, it may appear in literary works and even in texts In daily science activities, there are often children who are most concerned about where the "brightest Polaris" in the sky is. This makes the science workers laugh and cry - look at the starry sky. Polaris is only second-class in brightness, far less than Vega and Altair, which can be easily seen by naked eyes in the night sky of Shanghai. In reviewing his son's lessons, Tang Haiming found that in the second volume of the first grade primary school of Shanghai Education Edition, there was a text "children counting stars", which described the childhood story of Zhang Heng, a great astronomer in ancient China. In the text, "not far from them (Big Dipper), there is the brightest star, called Polaris.". '
In order to reflect the theme of literary works, it is not wrong to emphasize or exaggerate appropriately, but the editor may mark the truth of Science in the notes to avoid misreading 'said Tang Haiming.