August 20, 2015. “rainbow” forum at Lecture Theater Excellence was presented by Li Zhen Ru. The talk was attended by Principal, deputy principal, tutors from both department and students at Pusat Tingkatan Enam Tutong. His talks include the definition of rainbow, how it is formed and types of rainbow
He sets about how rainbow is formed. He explained that rainbow occurred when there is sunlight and rain. When light passes through a rain droplets and then the light will be reflected into 7 different colors which is red, orange, yellow, green, blue, indigo and violet and eventually entering our eyes. Red lights are bend outward while violet bend inwards. This is because of the wavelength. Red lights have wavelength of 650 nm while violet lights have wavelength of 400 nm. Therefore larger wavelength which is red will bend less. That is why the red lights are bend outward. We cannot see the violet lights because it is spread more since it has shorter wavelength.
In his talks, he also mentioned about types of rainbow which are double rainbow, full circle rainbow and circumhorizontal rainbow. First he explained about double rainbow which is when the lights are reflected twice and he also shows the audience a few pictures of that kind of rainbow. Secondly, full circle rainbow is where you can view it at a very high places so that you can see the whole things. This type of rainbow are very quite rare. Lastly, circumhorizontal rainbow are formed when light passes through ice crystal at atmosphere.
During answer and question session, he was able to answer questions asked by tutors and as well as students. One of the question is “If you want to see a rainbow, you are standing in front of the sun or behind the sun?”. Li Zhen Ru response towards the question, “The sun should be at the back and then the water droplets must be in front of you so that the light from your back enters and you will able to see rainbow in front of you. And one more thing is that, people won’t see the same rainbow which means that different angle will give different view of rainbow”.
We would like to thank Li Zhen Ru for delivering his talk and to all audience for coming to our forum.
Due to unforeseen circumstances, we apologized for the late update.
To watch the lecture, check it on Youtube
Click here: https://www.youtube.com/watch?v=rliNC7TOIGQ