在世界大大小小的比賽里，我們經常看到幸運者們滿臉自豪地舉起金燦燦的獎牌，這些金牌承載著榮譽與驕傲。然而金牌真的是用純金做的嗎？就讓下面這篇文章來為你解答吧！

Actually gold medals are not made of solid gold. They consist of chiefly gold, and silver, copper and other metals. Why are gold medals not made of solid gold? The reason is that solid gold (the gold content is 99.99%) is too soft. A fingernail scratch would be able to damage the medal and it would lose its shape easily.

Twenty-four karat gold is solid gold. Those which add other metals are called k gold. The gold content of 1k gold is 4.1666%. Thus, we can calculate the gold content of all kinds of gold metals. The formula is the degree of k gold times the gold content of 1k. For example, there is a gold medal weighing 100g. The gold content of a 22k gold medal is 91.6652g. 24k gold is the maximum degree of k gold.

In daily life, the size and gold content of gold is decided by the law of competition and the importance of the programmers. The diameter of the biggest gold medal is 10cm so far, and the smallest one is about 1cm.

solid gold：純金

（北京林業大學通訊員 邢元媛 供稿 英語點津 Annabel 編輯）