2. History and the concept of time
1. Fill in the blanks.
(a) The calendar wee use today is based on the Christian era or Common era.
(b) The period before the common era is known as the time Before the common Era (BCE) or Before Christ (BC).
2. Answer each question in one sentence.
(a) Which scientific methods are used to estimate the age of the layers of the soil and the remains found in them?
Ans. The dating techniques such as the Carbon – 14 analysis and the Tree-rings analysis (Dendrochonology) are used to estimate the age of the layers of soil and the remains found in them.
(b) How is the first century of the Common Era written?
Ans. The first century of the Common Era is written as 1 – 100 CE or 1-100 AD.
3. Answer the following questions in brief?
(a) What is meant by the unilinear division of time?
Ans. Seven days makes a week, two weeks makes a fortnight, four weeks makes a month. Twelve months make a year, 100 years makes a century. Ten centuries or 1000 years makes a millennium. Such a method of diving time is called unilinear division of time.
(b) What are the units of measuring time?
Ans. The units of measuring time are, second, minute, hour, day, week, fortnight, month, year, century and millennium. A second is the smallest unit of time. There are various methods of measuring time in different parts of the world. Of these the Common Era or Christian Era is most widely used.
3. Complete the chart given below.