Term 1 Week 4 - Investigation of Law of Reflection

During a practical session with the class of 2E1 pupils, they investigated the light phenomenon of 'Reflection' through a mirror. The diagram as seen from the practical worksheet is as shown below.

Diagram of the experimental setup
(extracted from CPDD resource for Lower Sec Science Package)

The pupils were not taught the theory concept of the laws of reflection but were expected to learn to follow the procedure of the investigation and to translate the diagram setup to actual setup. The intention was to allow the pupils to explore the reflection phenomenon and to infer from their observations and measurement of the angles the laws of reflection. In doing so, pupils also need to learn to read the procedure carefully before they commence on the investigation and subsequently the measurements of the angles. Initially, most pupils faced difficulties in interpreting the diagram and understanding the procedures. The instructions and steps are as follows:-

1. (Pair-work) "You will work with each other and read the procedures and study the diagram before you commence. Time given is 10 minutes for you to setup the apparatus and to measure the angles to fill in the table as provided. Later, I will select 2 to 3 pairs to present their interpretation of the investigation to the class." (skills: teamwork, meticulous reading, focusing and commitment to succeed)

2. Teacher commented on each presentations and give her inputs and praised the efforts of the pupils who presented. (skills: confidence-building and willingness to make mistakes and learn from their peers, students who were unsure know how to perform the experiment more confidently)

3. Pupils traced the rays and measure the angles and record into their practical worksheets. Subsequently, they answered inference questions to summarize their investigations.

Youtube Video on the experiment

The Youtube video has shown an easier method to obtain the angle of incidence and reflection. We could consider using this way to allow pupils to focus on observations at lower secondary level and to later elaborate on the drawing of ray diagrams.