I love color.  My clothes are arranged in rainbow order.  I can spend hours re-arranging my yarn stash into different color combinations.  Even my PhD thesis was inspired by the diversity of pigmentation in cultures of Trichodesmium.

Extracts of Trichodesmium spp.:  the pigmented cells that launched a thesis.

Extracts of Trichodesmium spp.: the pigmented cells that launched a thesis.

Gogo Squirrel asked me to help her teach creative arts in her 2nd grade class, and I peeked over her shoulder as she flipped through her South African curriculum.  The color wheel popped out at me.  Forget symmetry or bean mosaics, I wanted to teach color theory.

Droplets of rain acting as tiny prisms to form a rainbow over the school.  Alas, how I miss rain.

Droplets of rain acting as tiny prisms to form a rainbow over the school. Alas, how I miss rain.

Our perception of color is a combination of physics and biology.  Visible light covers a small range of wavelengths in the electromagnetic spectrum (400 – 700 nm), and these wavelengths can be separated by a prism into a visible rainbow.  Our eyes have three different kinds of cones that detect red, green, and blue, and with those three channels we can detect millions of colors.  Remove any one of these cones, and you get color-blindness.  The mantis shrimp has 12 cones. That’s insane.

There is some overlap in the detection wavelengths for human cones, especially for red and green, resulting in fun effects.  Concentrated yellow food dye looks red.  Green or yellow algal cells can produce a red tide; ocean water goes from blue to green to red as more blue/green light is absorbed, red light is backscattered, and the upwelling color hits the sweet spot between human red and green cones (570 nm) when a bloom develops (Dierssen et al, 2006).

When South African students learn about the human eye in grade 12, all the detail they are given is that the retina has rods and cones.  No red-green-blue, no shift from yellow to red, no understanding of why chlorophyll appears green.  They study the genetics of color-blindness without understanding what makes a person colorblind.  I have to get my color fun in the fundamental phase.

Well, if they aren't used for Winogradsky columns, the bottles may as well be used for color theory.

Well, if they aren’t used for Winogradsky columns, my bottle collection may as well be used for color theory.

In Gogo Squirrel’s 2nd grade class, I made a color wheel for them.  I used food dye in soda bottles to show them how primary colors mixed to form secondary colors, and they did their own color mixing with play dough.  After rolling balls and snakes to our hearts’ content, we drew flowers. Gogo Squirrel was very strict; each flower must be the right size and have exactly five petals.

After admiring the color display in 2nd grade, the grade R teacher asked me to repeat the lesson in her class.  It was a big hit.  Mixing colored water elicited awes and applause.  It’s wonderful to watch a child’s first experience with play dough, and they somehow managed to keep it out of each others’ hair.  They are young and new to school, so their flowers were wild and unconstrained.

The ladies of Grade R display their snakes.

The ladies of grade R display their snakes.

As my grade R kids grow up and learn about the electromagnetic spectrum, I hope they think about chlorophyll and why it’s green.  When they learn about photosynthesis, I hope they think about the elctromagnetic spectrum and how pigments are tuned to absorb specific wavelengths.  I hope their flowers stay wild and unconstrained.

A selection from the masterpieces of Grade R.  Note the dutiful presentation of complementary colors on the left.

A selection from the wild masterpieces of grade R. Note the dutiful presentation of complementary colors on the left.

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Trichodesmium colony

My puffy friend, Trichodesmium thiebautii strain VI-1

I need a stage name.  I love the ocean and I love East Africa, so I thought I would try to find a Swahili name for the tiny little plant-like critters I spend so much time studying–phytoplankton.  Through some friends, I’ve found some words and through a kamusi (dictionary), I have found some double meanings.

  • kijimea – phytoplankton/microscopic algae.  I think it’s a cute word.  But it can also refer to bacteria in general, which invokes sort of a yucky feeling in many people.  I don’t speak German, but kijimea appears to be some sort of immunity-boosting supplement in Germany as well.  Spirulina, anyone?
  • ngai – red algae.  Also “God” in many Bantu languages.  Must be a mighty alga!
  • ugozi – green algae, especially the scum that grows in stagnant water.  Also racism.  There’s a story there somewhere, or at least a very interesting metaphor.