Colors of light

Heavy morning rain knocked out Kacifica satellite connectivity for the campus.

I ran a hotspot off of my phone to connect my laptop to the Internet and then used my HDMI cable to display the morning Limits of Light video on the computer laboratory smartboard. This worked, with some loading stalls. The students on this campus are accustomed to video loading stalls that come with rainy days. 

I did not have access to a microscope, so I attempted to resolve the phosphors on the Smartboard using the macro camera on my phone. That failed, although one can see that there is an underlying structure to the image.

Elise

After the video I had the students view the visible spectrum using a CD spectrograph.

In experimenting here, I found that I could deliver a spectrum off of the top half of the CD disk while blocking the direct reflection of the opening with a piece of sandpaper. This worked surprisingly well.

As usual, the camera sensor does not produce the smoothly changing colors seen by the human eye. The abrupt change from yellow to green is not evident to the human eye and there is more blue and less purple visible to the human eye.

The dark band in the green is actually perceived to occur in the yellow by the human eye and could be a sodium absorption dark band effect - perhaps. 

I asked the students to name the colors that they are seeing. The students said they saw red, orange, yellow, green, blue and purple. I asked whether there was another color between blue and purple in the box and no one saw a color that was not bluish-purple between blue and purple. I asked about the colors of the rainbow and a student who had taught eighth grade noted that he had taught the students "ROY G BIV" - that these were the colors of the rainbow. That the rainbow has seven colors is taken as a fact, even though this is contradicted by what they have seen in the sky and what they saw in the spectrum box. Never let an observed fact stand in the way of a memorized belief.

After covering the rainbow I showed the students the Himawari satellite feed site and that a number of the bands available referenced "RGB" - red, green, and blue. Two of the students are working with the weather service here on Kosrae.

Himawari-8 heavy rainfall potential areas included Kosrae this morning

Renee-Ann-Seshrue finds the #F0F is magenta

I then had the students engage in the laboratory ten exploration of RGB color space.

CharlynRose found that #F90 is orange

With no CIS majors present, I spent less time and emphasis on HSL and X11 colors. 

I did cover Loomatix' Color Grab for Android as a tool for capturing and conveying color information. This is of relevance to sewing "uniforms" here on Kosrae - shared church wear.