一次有趣的科學實驗三年級英語作文
【一】
In ancient times, many people believed the earth was a flat disc. Well over 2,000 years ago; the ancient Greek philosophers were able to put forward two good arguments proving that it was not. Direct observations of heavenly bodies were the basis of both these arguments. First, the Greeks knew that during eclipses of the moon the earth was between the sun and the moon, and they saw that during these eclipses, the earth's shadow on the moon was always round, they realized that this could be true only if the earth was spherical, If the earth was a flat disc, then its shadow during eclipses would not be a perfect circle; it would be stretched out into a long ellipse. The second argument was based on what the Greeks saw during their travels. They noticed that the North Star, or Polaris, appeared lower in the sky when they traveled south, in the more northerly regions, the North Star appeared to them to be much higher in the sky. By the way, it was also from this difference in the apparent position of the North Star that the Greeks first calculated the approximate distance around the circumference of the earth, a figure recorded in ancient documents says 400.000 stadium, that's the plural of the world stadium. Today, it's not known exactly what length one stadium represents, but let's say it was about 200 meters, the length of many athletic stadiums. This would make the Greeks estimate about twice the figure accepted today, a very good estimate for those writing so long before even the first telescope was invented.
【二】
上科學課之前,老師讓我們帶熟雞蛋、太空泥。我一直在納悶,這些到底是幹什麼用的呢?今天謎底終於解開了。
上課了,老師讓我們兩人一組,每組準備一盆水,然後老師説:‘咱們要把浮在水上的東西沉下去,那沉下去的東西浮上來。“我首先把雞蛋放入水中,發現雞蛋是沉下去的,怎麼樣才能把雞蛋浮上來呢?我的問題又來了,不一會,我把雞蛋用手浮到水面上,一鬆手,雞蛋就沉下去了。我不放棄,又想把太空泥裹在雞蛋上會怎麼樣呢?我二話不説,立刻把太空泥裹在雞蛋上,放入水中,雞蛋就浮上來了,我的`臉上露出了微笑,心裏想吃了蜜一樣甜。接着,我又把太空泥放入水中,太空泥是浮起來的,我想把一點重物加在太空泥裏,會怎麼樣呢?我開始躍躍欲試,我一邊做,一邊嘴裏説:”先加一點重物,再放入水中。“不一會兒,太空泥就沉下去了,我的實驗又獲得了成功。我高興極了,科學實驗真的太有趣了。
-
【精華】春天的雨的作文合集9篇
無論是在學校還是在社會中,大家一定都接觸過作文吧,根據寫作命題的特點,作文可以分為命題作文和非命題作文。那麼你有了解過作文嗎?下面是小編精心整理的春天的雨的作文9篇,希望對大家有所幫助。春天的雨的作文篇1聽,那淅瀝淅瀝的響聲,聽那噼噼啪啪的撞擊聲。這就是我...
-
(合集)家為題的作文10篇
在平凡的學習、工作、生活中,大家總少不了接觸作文吧,作文是一種言語活動,具有高度的綜合性和創造性。怎麼寫作文才能避免踩雷呢?下面是小編幫大家整理的家為題的作文10篇,僅供參考,歡迎大家閲讀。家為題的作文篇1瞧,那個娃娃,個頭矮矮的,身材瘦瘦的,頭髮短短直直軟軟的,...
-
【推薦】四年級作文集合8篇
在日常生活或是工作學習中,大家對作文都再熟悉不過了吧,藉助作文人們可以實現文化交流的目的。你知道作文怎樣才能寫的好嗎?下面是小編精心整理的四年級作文8篇,僅供參考,大家一起來看看吧。四年級作文篇1給我家的兩隻小倉鼠換籠子時,它們突然在紙袋裏打架了。首先,倉...
-
寫國小的作文300字(合集3篇)
在日常學習、工作抑或是生活中,大家或多或少都會接觸過作文吧,作文是一種言語活動,具有高度的綜合性和創造性。一篇什麼樣的作文才能稱之為優秀作文呢?以下是小編收集整理的寫國小的作文300字3篇,供大家參考借鑑,希望可以幫助到有需要的朋友。寫國小的作文300字篇1秋...