The effect of guided discovery on students' Physics achievement

The study investigated and contrasted the relative effectiveness of guided discovery, demonstration and traditional lecture method of teaching on students ’ achievement in rotational motion. Grade 11 students from three selected preparatory schools in Ilu Aba Bora Zone located in southwestern part of Ethiopia took part in the study. The specific research design adopted in the study was pretest-posttest nonrandomized control groups experimental design. A purposive sampling technique was used to select three preparatory schools out of six preparatory schools in the zone. The whole research process took place within the natural classroom setting. The guided discovery, demonstration and the traditional methods were implemented in Mettu, Yayo Aida Thea and Gore Secondary and Preparatory Schools, respectively. The total number of students who took part in the study were 114 comprising of 73 males and 41 females. Researcher developed physics achievement test (RDPAT) with internal consistency of 0.77 using Kuder-Richardson formula 20 for pretest and 0.80 for posttest was used as data collection instrument in the study. The first semester result of the students who took part in the study was also used from the students ’ rosters to establish the construct validity of the RDPAT test. The statistical tests used in the study were mean and standard deviation, ANCOVA, t-test, ANOVA, Scheffè post hoc test, Cohen’s d and η2 effect sizes. Kolmogorov-Smirnov test was used to test the normality of the posttest scores, which is a key assumption in t-test and ANOVA. Analysis with ANCOVA and Scheffè test showed that