The source is of value and significance to the hypothesis because the hypothesis is to test whether the particular part of the Thukela river displays upper course characteristics and the encyclopaedia distinguishes between the characteristics and features of a typical upper course river, middle course and lower course river. The source of information is classified as a secondary source in the form of an encyclopaedia which provides definitions and visual explanations of a variety of topics. This nature of source allows the information to be supported by various perspectives and referenced sources to provide more constructive and holistic information. This is evident because the encyclopaedia lists many qualified contributors to the information provided and acknowledges many respected museums and institutions such as NASA.
Limitations of the encyclopaedia is that it is constrained by being unable to provide all information on the particular topic due to the information being summarised. Concise definitions and brief explanations of terms do not allow for vast sources of information and a variety of different methods of explaining the appropriate terms. There is limited space for a variety of perspectives and additional information such as scientists’ opinions and viewpoints on particular topics because the encyclopaedia needs to remain absolutely factual and objective in order to serve its sole purpose of providing concise definitions. There are over 25 000 terms that are defined in the encyclopaedia and consequently there is a limited amount of space to provide brief explanations for every term.