Radiometric Dating 同位素年代测定
- Radioactive Decay/ Nuclear Decay 衰变
- Half-life 半衰期
衰变，是某些原子核自发射出某种例子儿边为另一种核的过程。
半衰期（英语：Half-life）是指某种特定物质的浓度经过某种反应降低到剩下初始时一半所消耗的时间。在物理学上，一个放射性同位素的半衰期是指一个样本内，其放射性原子衰变至原来数量的一半所需的时间。
Radiometric dating calculates an age in years for geologic materials by measuring the presence of a short-life radioactive element, e.g., carbon-14, or a long-life radioactive element plus its decay product, e.g., potassium-14/argon-40.
放射测年法，又称放射性年代测定法，是利用测定被测定物中某些放射性同位素与其衰变产物的比率，之后应用这种放射性同位素半衰期计算年代的方法，亦被称为绝对测年法
生物存活的时候，C12/C14的比率是一定的，因为不断与外界进行物质交换。但当生物死亡以后，这个比率开始发生变化，比率有一个衰退的时间周期，通过测定这个比率，可以根据对照表，推断出其生活的年代。
Relative Dating & Absolute Dating
C14 dating is Absolute dating.
Archaeologists have two main ways to tell the age of sites and artifacts. Relative dating tells how old something is in relation to other objects, but cannot provide a year or specific date of use. In contrast, absolute dating provides a specific calendar year for the occupation of a site.
Relative dating methods estimate whether an object is younger or older than other things found at the site. Relative dating does not offer specific dates, it simply allows to determine if one artifact, fossil, or stratigraphic layer is older than another.
Absolute dating methods provide more specific origin dates and time ranges, such as an age range in years. How specific these dates can be will depend on what method is used.
Words
- excavate 发掘
- excavation sites 发掘地点
- paleolithic 旧石器时代（hunting-gathering, nomadic life）
- mesolithic 中石器时代
- neolithic 新石器时代(settlement, livestock, agriculture)
- lithosphere 岩石圈
- chronological 年代的
- remain 遗骸（剩下的东西）
- Pottery 陶器
- Ceramics 陶瓷的
- antique 古老的
- artifact 手工艺品
- peat 泥炭
- surmise 推测
- occurrence 出现
- made of: material，由…制造的
- dump 垃圾场,垃圾，倾销
- skeuomorphs 纺织品
- ceramics 陶瓷
- bronze cauldron 青铜大锅
Articles
Pottery
- Kinds of archaeological evidence that pottery provides
- Why does the professor list several reasons that pots were traded? To support her claim that pottery provides evidence of distribution
- According to the professor, what is one reason it is important to study the material from which pottery was made? It can help archaeologists establish where the pottery came from
- According to the professor, why is it difficult to gain information on the function of a pot? (Click on two answers.) 1.Not all pots found in the same location have the same function; 2. Pots are rarely found in the places in which they were used
- What is a skeuomorph? A copy of an object, but made from a different material
Pottery can provide such evidence:
- dates, styles
- evidence of trade and distribution
- evidence of function