INTRODUCTION
In 1977, Apple Computer popularized personal computing – Jawa. How to program 6th Edition (2006). Many institutions followed the trend of computer evolution to include computer science in those students curriculum both in the junior and senior secondary school level.
In Nigeria some of the junior secondary schools offer computer science as one of the subject contained in the school curriculum.
The work is an attempt to identify the difficult teaching –learning topic in junior secondary school computer science curriculum in Nigeria.
1.1 BACKGROUND OF THE STUDY
The evolution of computer in Animanjo (2007) shows that almost all the inventors in the field of computing are mathematicians and that computer machine language generally consist of strings of numbers (ultimately reduce to Is and Os) that instruct computer to perform their most elementary operations one at a time. Some of the junior secondary school computer science topics are mathematics related. And according to Eze (2006) said that mathematics is a subjects that has been found to be feared and disliked by a lot of pupils ad students. According to Eze (2000) also asserted that mathematics is core subject in that both primary and secondary school in Nigeria but amazing it has become a masquerade and students fail mostly the science subjects in public examinations, some even drop them with out understanding that they are basis of strong foundation in science.
World education Encydopadia Vol 3 (2002) asserted that one of the governments major concerns regarding basic education has been the goal of up grading the qualification its schools teachers.
Teachers are the most important “driver” in any education settings. They are like a car driver that determines which directions the students should be taken to. The way the students look at the teacher is the some they perform in the classroom. This is possibly posed the reason for Ejili and Anyanwu (2006) said that “a good teacher has the managerial and administrative skills of ensuring a conducive teaching and learning environment, such a good teacher can effectively manage the classroom and the actives of the learner and encourage the learner to develop positive self concept, good vales, attitude and belief but drop falsehood as believing that a subject topic is hard without one-in-one encounter or experience. The teacher should be good at lesson presentation skills because what the student hears at the beginning or at the end is often remembered. If not presented properly the students may perceive wrong information. For instance computer is usually known by the slogan: GIGO” that is garbage in garbage out meaning that whatever you give to computer, computer will give to you back. Computer programming deals with codes and if these codes are not carefully presented, students may perceive it difficulty.
There is no doubt that the teacher real battle is concerned with training of the total child and the application of knowledge in his daily life. The teacher are therefore faced with the problem of resource materials the textbooks. Kamalana (1971) observed that the quality of textbooks suitable for Nigeria school have not improved but the teachers are better placed to select teaching materials from the books that are available to them. Some of the problems confronting science education include: difficulty of attracting and retraining qualified science teachers as well as the inadequate library facilities in science subjects. This is why Agogo (1988) stated that science teacher is a legacy of the past but that it is rather getting worse due to the explosive expansion of the primary and secondary education in Nigeria today.
As the thirst for western education grew among Nigerians, more subjects were introduced into the school system. These change were eminent and timely for Nigerians to develop scientifically and technologically. The teachers shortage is a snag to achieving. This objective, Aleyiderio (2000:23) observed that is regrettable that the teaching profession is still saddle with a vast army of professionally unqualified staff and that greater shortages, especially in some crucial subject areas have continued to plague the educational system. Yet no educational system can rise above the quality of its teachers, said in Nwuche and Odo (2007) according to the National policy on Education (2004:8).
Education shall continue to be highly reeled in the national development plans because education is the most important instrument of change, any fundamental change the intellectual and social outlook of any society has to be proceeded by an educational revolution.
This, the same document, the NPE (2004) give the major aims of secondary education as: (a) Preparation for useful living within the society (b) preparation for higher education.
i) It gives the specific objective to include: opportunity for education of a higher level, irrespective of sex, social, status, religious or ethnic background.
ii) Offer diversified curriculum to center for the differences in talents, opportunities and future rotes.
iii) Provide technology and commerce at sub professional grades.
iv) Foster National unity with an emphasis on the common ties that ultimate us in our diversity…..etc. Education is the best legacy a nation can give to her citizens especially the youth. According to Olutu (1994).
In the guest of finding survival fact, the nation has evolved series of socio economic and educational measures and policies or programmes may be to improve the teaching –learning topics among teachers and students. But the inconsistent continuation of educational laws and policies since (1970:5) till the present time, has brought a different story.
According to Shihu (2009) this gradually laid the foundation of fallen standard in education at the primary and secondary school levels.
The fact that pupils fail to understand science and thereby perform poorly in junior secondary computer science does not mean, they are “dullards”, but to some underlying factors which might not be unconnected with the teachers teaching style content and concept difficulty as perceived y the both teachers and pupils. So the interest of the learners towards a particular subject will affect their achievement. Those who develop negative interest in science will invariably perform poorly too. Some pupils even act on wrong information passed to them by their seniors that “science is difficult to learn”. This usually affects the achievement level of the students and this is why Akpan (1986) informed that even though science is skill foreign to African and it should be taught with caution. It means that teachers have to be better oriented about teaching as a profession.

1.2 STATEMENT OF THE PROBLEM
As the inclusion of the topic: identification of difficult teaching-learning topic in junior secondary school computer science curriculum” as a research topic and from these background so far, questions that agitate these researchers minds are:
1. What are the computer science concepts that teacher, perceive difficult to teach?
2. What are the effect of those difficult concepts on the performance of the pupils.
3. What difficulties do female teachers perceive in computer science concepts more than male computer subject.

1.3 PURPOSE OF THE STUDY
According to Ibeamuka (1996:18) many pupils have problems in learning science at higher level because many of them are not ready intellectually for their career in teaching. Other pupils develop negative attitude towards science, even at the primary school level because they are made to learn science very theoretically. Based on the observation made above many pupils tend to develop negative attitude towards science subject right from on set.
The purpose of this research is to identify the difficult teaching-learning topics in junior secondary school computer science curriculum and specifically. This study is designed to.
1. What are the computer science concepts that teacher, perceive difficult to teach?
2. What are the effect of those difficult concepts on the performance of the pupils.
3. What difficulties do female teachers perceive in computer science concepts more than male.

1.4 RESEARCH QUESTIONS
The following research questions are put forward for the purpose of testing.
1. To what extent does the computer science teachers perceive some concepts difficult to teach?
2. What are the effect of those difficult concepts on the performance of the pupils.
3. What difficulties do female teachers perceive in computer science concepts more than male.

1.5 RESEARCH HYPOTHESIS
There in a significant difference in teaching and learning of computer science in junior secondary school in Enugu State education zone.

1.6 SIGNIFICANCE OF THE STUDY
This study intends to examine school computer curriculum, to find out the topics that teachers perceive difficult to teach in order to overcome the serious malady of low achievement. This is necessary because Nigeria is presently technologically under developed, aspiring to be developed scientifically.
Specifically, this study is considered to be significant because when the concept that the teachers perceive difficult are identified, ways to address them would also be soughted out it would then help to increase both the enrolment figure and the achievement levels of pupils.
The theoretical significance is based on the work of David Ausubel’s meaningful learning. This is because it is important for both the teachers and the students to take cognizance of their previous knowledge visa-vis the incoming knowledge to make meaning out of what is taught and learnt if the incoming knowledge are not related to the existing ones, then both the teacher and the students would have problem enchoring the new knowledge. Such concept may therefore be perceived difficult.

1.7 SCOPE OF STUDY
The scope of this research is focused on identifying difficult teaching-learning topics in junior secondary school computer science curriculum in Nigeria. A case study of Enugu educational zone.

1.8 DEFINITION OF THE BASIC CONCEPTS
Identifying according to the new international Webster’s comprehensive dictionary, is to determine or establish as a particular person or thing.
1. Teaching-Learning: This is the act of giving lesson by the teacher in a subject to a class or pupils and pupils on their part, will gain knowledge through study.
2. Junior Secondary Education: This is referred to the education given on institution for children, children receive the education after primary education and before the senior secondary stage.
3. Computer Science: Simply put, is the scientific study of computer and computer itself, is an electronic device that accepts data as input and processes them electronically to produce the desired output of information with the aid of a set of instructions.
4. curriculum, according to Onwuka (1990) is a structural series of intended learning experience. It is structured in that it has definite parts or sections. This parts or sections refers to the number of fixed subjects with set body of knowledge taught by teachers and learn by pupils.