This paper presents a model program for high school computer science education. It is based on an analysis of the structure of the Israeli high school computer science curriculum considered to be one of the leading curricula worldwide. The model consists of four key elements as well as interconnections between these elements. It is proposed that such a model be considered and/or adapted when a country wishes to implement a nation-wide program for high school computer science education.

One of the units in the relatively new high school CS curriculum which is being implemented in Israel is a theoretical unit on computational models. It includes deterministic and non-deterministic finite automata, regular and non-regular languages, closure properties of regular languages, pushdown automata, closure properties of context free languages, Turing machines, the Church-Turing thesis and the halting problem. This paper focuses on part of a study we conducted dealing with the achievements of high school students studying this unit. Specifically, this paper compares the achievements of students on the technical parts of this unit vs. its theoretical parts. We also examine the correlation between achievements of students studying the Computational Models unit, and two other factors: The students' previous computer-related background (not necessarily computer science) and the level on which they studied mathematics.

The ongoing debate among Computer Science educators about the advantages and disadvantages of the shift from the procedural to the Object-Oriented paradigm usually relates to the introductory course. Indeed, we were also concerned when in our institute we decided to implement this shift in our introductory course and started to teach Java, instead of a procedural paradigm. In our previous study we saw that the effect of the shift did not lower the achievements of students taking the CS1 course. Furthermore, we wanted to be equally sure that this was the case when students take Data Structures courses. This is the focus of the study presented in this paper. The results show that there is no significant difference in the achievements of students who came from different paradigm backgrounds. This encouraging result probably relates to the fact that our CS1 course focuses on the fundamentals of introductory Computer Science and does not only emphasize the language aspects.

This paper describes research on the perception of undergraduate students of the concept of reduction. Specifically, based on an analysis of students' answers to questions addressing different CS topics, we present several findings regarding the ways in which undergraduate students conceive of and apply reduction. In addition to the research description and results, the paper discusses the role of reduction in CS and suggests several teaching applications.

For some time, there has been an ongoing debate among Computer Science (CS) educators about the advantages and disadvantages of the shift from the procedural to the Object-Oriented (OO) paradigm. In our institution, we decided to implement this shift in the year 2005, when we changed our introductory course and started, right from the beginning, to teach the Java language, instead of the procedural facet of C++. While we still offered the two different paradigms in parallel, we had two similar groups each taking one of the paradigms. These two groups served as the research population of the study we describe in this paper. We examined whether the shift from the procedural to the OO paradigm had an effect on students' perception of fundamental concepts taught in the introductory course.