1.0 INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Class size appears to be one of the crucial elements that is often considered by educational planners in order to achieve the set out objectives in any educational system. This is because of the obvious negative implication of our crowded classroom on the teacher and the learner. Ozochie (2009) opined that to make the correct estimate of the resources needed is the function of population. This point suggests that the essence of having a definite number of learner in a classroom is to ensure that the resources which includes the teacher, the instructional materials, class space, seating arrangement among others are adequately provided for smooth teaching and learning.
Apart from the need for adequate provision of resources, effective teaching and learning seem to be the function of the teacher understanding the individual differences of each of the learner as this forms the basis for the appropriate teaching skill to be applied. Onah (2008), aptly notes in this regard that the essence of having a manageable class size is to ensure that the understanding rate of each of the learner, their respective general background are put into consideration by the teacher in the course of his teaching.
Teaching and learning of computer science, like every other branch of natural science requires observation and learner centered activities. In order to achieve result, the teacher should ensure that he monitors the activities of the learner. As Anne (1990) rightly notes and portrays science as the entire problem. Solving child centered purposeful set of activities within a coherent and structured frame work. This cannot be achieved unless it can be translated into meaningful action. For Anne, this requires more than simply presenting children with organized problem rather such becomes meaningful when the purpose of the activities becomes me aningful, explicit and shared between children and teacher and placed under a class that could be managed by the teacher. Under an overcrowded classroom environment, the learner-centered activities would pose great challenge to the teacher hence the desired behavior change may not be easily achieved. It is therefore the thrust of this study to find out the effect of class size in effective teaching learning computer with particular reference to junior secondary schools located in Enugu North Local Government Area.

1.2 STATEMENT OF THE PROBLEM
The national policy on education revised in 2010 stipulates that the maximum teacher –student ratio is one teacher is to thirty students. The obvious reason for this standard is to ensure that the teacher not only controls the class but also to ensure that he understands the learning capabilities of each of the learner in the classroom. Ozochi (2008) affirms that there is a limit to which a teacher can effectively control, anything more than that according to him will affect the school objectives.
However, in most of our secondary schools today the teacher –student ration has gone far beyond the stipulation of the national policy on education. Students stay more than fifty in each class, seating arrangement altered, thereby making teaching and learning difficult. Educational planners in Nigeria have attributed the over bloated class size due to the explosion of the population of children of school age. Recently the Enugu State Government through her agently spliced most of the secondary schools located within the metropolis in order perpherps to expel the agony of overcrowded classroom.
Computer science, like all other natural science is an activity based subject, a situation whereby the learner is exposed mainly to the practical learning process under the guide and supervision of a teacher. Maduagwu et al (1998) opines that effectiveness of a classroom management results when the teacher and student achieve the purpose of which either are together in a class under an overcrowded classroom environment like what obtains in most of our schools today it becomes pertinent to ask, how effective is teaching and learning particularly in subject area that requires close monitoring of the learner by the teacher.

1.3 PURPOSE OF THE STUDY
The following research purpose have been outlined for the study
1. To find out ways class size affects teaching and learning of computer science in junior secondary schools in Enugu North Local Government Area of Enugu State.
2. To examine the effectiveness of the policy guiding teacher-student ratio in junior secondary school computer science
3. To examine how effective is the use of instructional materials in an overcrowded classroom environment.

1.4 RESEARCH QUESTION
1. In what ways does class size affect teaching and learning of computer science in Enugu North Local Government Area of Enugu State.
2. How effective is the policy guiding teacher-student ratio in junior secondary school computer science class in Enugu North Local Government Area of Enugu State
3. How does class size affect the use of instructional materials in junior secondary school computer science class in Enugu North Local Government Area of Enugu State.
1.5 SIGNIFICANCE OF THE STUDY
1. The study when completed would enable the teacher and or instruction know the dangers associated with over-crowded classroom.
2. It would assist the government and education planner on recruitment and supervision of teachers bearing in mind the expected teacher-learner ratio.
3. The study will assist in providing a guide in the realization of one of the core objectives of Nigeria education which is to make Nigeria one of the technological advanced countries in the world.

1.6 SCOPE OR DELIMITATION OF THE STUDY
The study is limited to government junior secondary schools located in Enugu North Local Government Area.