Placeholder Image

字幕列表 影片播放

已審核 字幕已審核
  • If you ever find yourself gazing at falling snow, why not catch a few snowflakes on your glove and examine their shapes?

    如果你曾經看著白雪飄落並想著,何不抓住一些雪花放在手套上,看看它們是什麼形狀,

  • You might notice that they look symmetrical, and if you look closely, you'll see they have six sides.

    你可能會發現它們是對稱狀的,如果你看得更仔細,你會發現它們具有六個邊。

  • You could say a snowflake is simply frozen water, but compare one with an ice cube from the freezer, and you'll realize they're very different things.

    當然你可以說雪花不過是結凍的水,但與冷凍庫中的冰塊相比,你會發現雪花其實是非常不一樣的東西。

  • Unlike ice cubes, formed when liquid freezes into a solid, snowflakes form when water vapor turns straight into ice. But that still doesn't explain why snowflakes have six sides.

    不像冰塊是由液態水結凍成為固態,雪花是由水蒸氣直接結凍成冰,但這仍無法解釋雪花為何是六邊形。

  • To understand that, we need to delve deeper into the physics of water.

    為了瞭解這點,我們要更深入探討水的物理性質。

  • Water is made out of two hydrogen atoms and one oxygen atom. A single water molecule thus has ten protons and ten electrons, eight from oxygen and one from each hydrogen atom.

    水是由兩個氫原子加上一個氧原子構成,單一水分子便有十個質子以及十個電子,其中八個屬於氧原子,其餘兩個分別屬於兩個氫原子。

  • The two electrons from oxygen's outer shell are shared with two electrons from both hydrogens as they bond together, and the remaining four outer shell electrons from oxygen form two pairs.

    與氫原子鍵結時,氧原子外層中的兩個價電子會與氫原子共享,於是氧原子的外層便剩下四個電子,成為兩個電子對。

  • We call the bonds between these atoms covalent bonds.

    我們將這些原子 (氫與氧) 之間的鍵結稱為共價鍵。

  • The pairs of electrons are all negatively charged.

    電子對帶有負電荷。

  • Similar charges repel, so they tend to stay as far away from each other as possible.

    同電荷會互斥,因此電子對會盡可能地遠離彼此。

  • The pairs form four electron clouds, two of which are where the hydrogen and oxygen share electrons.

    所有的電子對形成四個電子雲,其中兩個由氫氧之間共享的電子形成。

  • The repulsion between the unbonded pairs is even stronger than repulsion between the shared pairs, so the two hydrogens get pushed a little further to an angle of 104.5 degrees.

    而未鍵結的電子對之間的斥力,遠比形成共價鍵的電子對之間的斥力來得強,因此兩個氫原子會被稍微推擠到,使兩共價鍵夾的角度成為 104.5 度。

  • The water molecule as a whole is electrically neutral, but oxygen gets a larger share of electrons, making it slightly negative and the hydrogens slightly positive.

    水分子整體是電中性的,但是電子會傾向於靠近氧原子 (氧電負度較高) 使得氧原子方向的電荷偏負 (負偶極),氫原子方向的電荷偏正 (正偶極)。

  • Due to its negative charge, the oxygen in one molecule is attracted to the positive charge of the hydrogen in another molecule, and so a weak bond between the two molecules, called a hydrogen bond, is formed.

    由於電荷偏負的緣故,水分子中的負偶極會被另一個水分子中正偶極吸引,於是兩個分子間便產生了微弱的鍵結,也就是所謂的氫鍵。

  • When water freezes, this bonding occurs on repeat, ultimately forming a hexagonal structure due to the angle between hydrogens and oxygen within each molecule.

    當水結凍時,氫鍵不斷生成,最後形成六邊形的結構,這是由每個水分子中氫原子和氧原子所夾的角度所造成。

  • This is the seed of a snowflake, and it retains a hexagonal shape as it grows.

    這便是雪花的核心,接著雪花便會依此六邊形逐漸增大。

  • As the snowflake moves through the air, water vapor molecules stick to the six sharp edges and expand the snowflake outwards, bit by bit.

    當雪花飄在空氣之中時,水蒸氣會依附在六邊形的邊緣,一點一點的逐漸增加雪花的體積。

  • A snowflake's developing shape depends on atmospheric conditions, like humidity and temperature.

    雪花最終的形狀取決於大氣的狀態,像是濕度以及溫度等。

  • As a snowflake falls, changes in weather conditions can affect how it grows, and even small differences in the paths two snowflakes take will differentiate their shapes.

    隨著雪花的飄落,氣象條件的改變也會影響其形狀,甚至只要路徑上一丁點的不同,就會在兩片雪花的形狀之間造成差異。

  • However, since conditions at the six sharp edges of one snowflake are similar, a symmetric snowflake can grow.

    然而,因為所有雪花的核心都是六邊形,所以所有的雪花都是對稱狀的。

  • Weather conditions affect snow on the ground, as well.

    氣象條件也會影響地面上的雪花。

  • Warmer ground temperatures produce a wetter snow that is easier to pack because liquid water molecules help snowflakes stick to each other.

    較溫暖的地面溫度產生的雪較濕軟,更容易堆疊,因為液態的水分子會幫助雪花抓住彼此。

  • Melted snow also plays a critical role in another wintry activity, skiing.

    融化的雪對另一項冬季活動也有很大的影響,那就是滑雪。

  • Completely dry snow is very difficult to ski on, because there's too much friction between the jagged snowflakes and the ski surface.

    完全乾燥的雪地是非常難滑的,因為雪花不平整的表面與滑雪板之間的摩擦力太高。

  • So what's happening is that as skis move, they rub the surface of the snow and warm it up, creating a thin layer of water, which helps them slide along.

    那麼,滑雪時究竟發生了些什麼事呢?滑雪板與雪面相互摩擦並產生熱,融出了一層水來幫助滑雪板前進。

  • So technically, it's not really snow skiing, but water skiing.

    因此,嚴格來說,這其實不是在滑雪而是在滑水。

  • But it is true that no matter how hard you look, you're almost definitely not going to find two identical snowflakes, and that's a mystery that scientists are still trying to solve,

    千真萬確的一點是,不論你看得如何仔細,你幾乎不可能找出兩片完全一樣的雪花,這項謎團仍有待科學家們來解答。

  • though we know that it has to do with the many possible branching points in snowflake formation, and the differences in temperature and humidity, and while we wait for the answer, we can enjoy watching these tiny fractals falling from the sky.

    目前我們知道的是,這可能和「雪花形成時可能產生分支的節點」有關,另外溫度和濕度的差異也有影響,而在我們等待答案的同時,可以一邊欣賞這些小小的結晶緩緩地由空中落下。

If you ever find yourself gazing at falling snow, why not catch a few snowflakes on your glove and examine their shapes?

如果你曾經看著白雪飄落並想著,何不抓住一些雪花放在手套上,看看它們是什麼形狀,

字幕與單字
已審核 字幕已審核

影片操作 你可以在這邊進行「影片」的調整,以及「字幕」的顯示

B2 中高級 中文 美國腔 TED-Ed 雪花 氫原子 電子 六邊形 電荷

【TED-Ed】雪花的科學 (The science of snowflakes - Maruša Bradač)

  • 14200 1505
    Yun Ting 發佈於 2021 年 08 月 06 日
影片單字