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Calcium is a silver-white metal, but you will not find a shiny bar of it in the kitchen. It hides inside other things. Your teeth and bones need it to stay hard; chalk and limestone are full of it as well. It is a chemical element, and its short symbol is Ca. On food labels and at the doctor's, people talk about “getting enough calcium” — milk, cheese, , and some green leaves are the usual advice. A British chemist, Humphry Davy, gave it this name in 1808 because he took the metal from lime. It is a school-and-health word, not a word for jewellery.
鈣
組成Coined in 1808 by Humphry Davy, from Latin calx (“lime, limestone”), because this metal is found in limestone. On the surface: calc- + -ium (the chemists' metal ending).
同家族的字
- calcifyto become hard, or make something hard, as this mineral builds up
原始詞典資料2 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
calciumnoun/ˈkælsi.əm/
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The chemical element (symbol Ca) with atomic number 20: a soft, silvery-white alkaline earth metal which occurs naturally as carbonate in limestone and as silicate in many rocks.
- Oxygen levels on Earth skyrocketed 2.4 billion years ago, when cyanobacteria evolved photosynthesis:[…]. The evolutionary precursor of photosynthesis is still under debate, and a new study sheds light. The critical component of the photosynthetic system is the “water-oxidizing complex”, made up of manganese atoms and a calcium atom.
- “This material has a specific hardness and is chemically very stable. It forms naturally from calcium alone, but bacteria accelerate the transformation into calcium carbonate,” explains Alejandro Montesinos, head of the Decarbonization, Climate Change, and Circular Economy Research Group at Tec de Monterrey and a member of the Institute of Advanced Materials and Sustainable Manufacturing.
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An atom of this element.
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。