2021-02-042021-02-04http://hdl.handle.net/123456789/692xiii, 174p. :ill.The purpose of the study was to design and develop assessment instrum-ents (tasks) to assess laboratory planning, performing and reasoning skills of physics students in selected senior high school topics in mechanics and optics. The accessible population was 551 SHS 3 physics students in seven schools within Sekondi-Takoradi metropolis. Two hundred and eighty nine students were sampled for the main study. Simple and stratified random sampling methods were employed in select-ing the students. The “basic skills assessment testing” method also known the “psychometric testing” approach was chosen for the study. The instruments used were three performance assessment tasks. Scoring formats were used to score the students’ responses. Another physics teacher was given 111 subsamples of the scripts to score. Inter-rater reliabilities for the tasks were: 0.93 for Task A, 0.96 for Task B, 0.94 for Task C, and 0.93 for the total tasks. Means, standard deviations, frequencies, percentages, t-tests and ANOVAs were estimated. Results and findings from the research show that (a) majority of the students demonstrated high levels of competency in laboratory planning, performing and reasoning skills; (b) Male and female students demonstrated similar levels of planning, performing and reasoning skills. (c) Particularly, students from girls schools exhibited higher proficiency in reasoning skills than girls from mixed schools. It was recommended that physics students should be given more opportunities to practice hands-on activities. It was also recommended that physics teachers should do more performance assessments in school.Laboratory skillsPhysics studentsHigh school physicsMechanics and opticsPsychometric testingThesis