There are two methods used in the classification process namely Ratio Carbon dating and Potassium Argon dating;
[*]CARBON DATING METHOD (Carbon xiv)
This method is useful in determining the ages of materials of biological origin (remains of animals and plants).
Human being breath in Oxygen and release Carbon dioxide then plants take in Carbon dioxide and release Oxygen during Photosynthesis process. When animals die their bones normal contain some minimum Carbon content also when plants die their remains consist of certain level of carbon. These Carbon contained in animal remains and plants at the point of Death is used to measure the age of that species because at the point of death both animals and plants stop taking in Carbon, and the remained carbon in both plants and animal remains decays at a constant rate, this carbon dioxide released at a constant ratio is known as Carbon 14. Carbon 14 Method can be used in dating objects which are less than 5000 years old. Stone and metals do not contain Carbon14 because they do not absorb carbon dioxide.
[*]POTASSIUM ARGON DATING METHOD
This method relies on the measurement of the Potassium that decays in Argon in rocks. The Earth is about 4.6 Billion years old, this method is use volcanic rocks to measure the ages of rocks because volcanic rocks have pores and so Potassium can penetrate to these pores and then decay slowly so the content of potassium decay at a constant rate.
It used to date early stone implement and fossil skull of early man found in Olduvai Gorge
- Written Records
These sources include letters, books, and diaries, annual reports, painting maps, magazines, newspapers, journals, novels, plays and documents. These records usually are found in libraries and in schools, colleges, offices and with individuals.
Advantages of Written records
Disadvantages of Written records
- They are permanent way of recording and storing of historical events.
- They are more accurate that oral tradition.
- They are cheaper than those of archaeology.
- They are easy to translate into other languages.
- It may be badly written.
- They may be biased.
- They may not up to date due to rapid changes in the world.
- They are limited especially to illiterate class.
- Some of them are expensive for example buying of books.
An Archive is the place where historical or government documents are stored. The record kept may be both private and public. In Archives there are some documents like colonial records, early missionaries, traders and different writings by prominent leaders.
Limitations of Archives
- Archives are very expensive to set up.
- Accessibility of archives is limited.
- They need protection since they are not easy to be replaced.
This is a place or building where objects like cultural, historical and scientific interests are kept and shown to the public. In Tanzania National Museum in found in Dar es Salaam and Village museum in Kenya.
Disadvantages of Museum
- It is expensive to maintain museum.
- Some museum lack trained personnel to run them.
- Most of museum charges entry fees.
- Audio – Visual/ Electronic Sources
These are the most recent sources of acquiring historical information, they include Television, films, radio, and video. They are modern scientific technology used to store information.
Advantages of Using Audio – visual sources
Disadvantages of Using Audio- visual sources
- They capture information as events take place.
- They capture words and emotions of an events such as radio and television.
TIME IN HISTORY
- Films are unrealistic in most cases.
- They are expensive.
- They consume time while shooting them.
In history time is estimated and approximated. Historians divide time into days, weeks, months, years, decades, generations, centuries, millennia, period and ages.
Time is an important element because it deals with events that took place at a specified period.
The following terms are used when referring time in History;
HOW TO DIVIDE TIME IN HISTORY
- A decade – A period of ten years.
- A generation – Is the average difference in age between child and his parent.
- A century- Is a period of one hundred years.
- A millennium – A period of one thousand years.
- A period – A time determined by one continuous event lasting for number of years, for example the period of British colonial rule in Tanzania.
- An Age – the time characterized by mankind economic situations and type of tools used for example during Stone Age or Iron Age.
In order to calculate time man used different types of calendars for example;
- Egyptians came up with solar calendars which had 365 days.
- Sumerians used the lunar calendars which had 354 days.
- Muslims used Hijri Calendar which consisting of 12 months in a year of 354 or 355 days, The first year of Islamic year begin in AD 622 during the emigration of Muhammad from Mecca to Medina
The standard system of numbering years is based on the birth of Jesus Christ. The starting point is known as year Zero (0). The year before Christ (BC) and the year after Birth of Jesus Christ are called AD Latin word (Anno Domino) which After Christ.
HOW TO DETERMINE DATES
In order to determine dates of an events Historians use different methods such as;
Sources And Importance Of History Evolution of man, Technology and Environment
- Recalling events- This method involves remembering of important events and changes that took place in a particular places for example occurrence of floods, arrival of strangers, presence of wars, famine. This method usually was used by people who cannot read and write.
- Language studies- Under this method dating are determined by looking at the vocabularies, sayings and literature of some languages. For example the word karafuu in Swahili language started to be used when cloves plantation were introduced in Zanzibar
- Scientific Methods- Date are determined through carbon 14. This methods is used in identifying archaeology findings of animals and plants whose age are beyond 5000 years
- Ordering of events- This involves the use of illustration of events, through the use of time charts and time line historians illustrate the chronology of an events