BATU, EAST JAVA – During my science lesson I wanted to demonstrate to students how a rainbow occurs. I encouraged students to conduct an experiment on making a rainbow. The afternoon sun was quite hot, and at 11.30 am the students of Grade VC were in groups on the school field. These two last lesson periods of the day were when teaching science was scheduled.
The students conducted an experiment on making a rainbow by trying to do it for themselves and communicating the concepts they had learned.
At the beginning of the lesson, I invited students to sing the song Pelangi (Rainbow), but with the lyrics changed. The words red, yellow and green were replaced with an acronym of the words red, orange, yellow, green, blue, indigo and violet (mejikuhibiniu in Indonesian).
The students sang Pelangi with each group forming a circle. Beforehand, they had to prepare the equipment and materials needed, namely a basin filled with water, a flat mirror, and white paper for a screen.
After they had finished singing the song, the students were given a worksheet on how to create a rainbow. First they had to be in a place where the sun was shining very brightly. Then, that sunlight was refracted and broken down by the water in the basin and it formed a rainbow. The reflection of the rainbow was projected onto the the white paper. "We managed to catch a rainbow," cried the Red Group. "We did too! Cool!" said the Blue Group. Then each group recorded the colors that appeared in the reflection of the rainbow on the white paper.
Some groups did not manage to capture the rainbow because capturing the sunlight and reflecting it with the mirror was a difficult thing to do. Each student was required to use their skill to focus the sunlight using the mirror.
Then, the students discussed the formation of the rainbow in this experiment, the role of the mirror and the water in the basin, the use of the paper, the colors they observed on the screen, and what the outermost and innermost colors were. These questions were the subject of discussion and were subsequently described and communicated through presentations. The lesson ended with presentations and the display of the results of the reports on the experiment.
This activity could be developed further using other materials to create an "artificial" rainbow such as prisms, old CDs, or spraying water.