Night Hike

Grade Level: Any

Objective: Students will learn about their senses and the way their bodies adapt to the dark.

(Photo by my father, Richard Button)

Materials: Flashlight, first-Aid Kit, radio (or phone), Wint-O-Green lifesavers, Skittles, plastic containers with strong scented object (I used cinnamon and hot chocolate mix), photoreceptor model drawn on an opaque ball, candle, lighter


On our night hike we:
-Discussed the photoreceptors near the back of our eyes--the rods (responsible for black and white vision and seeing movement) and the cones (responsible for seeing color and detail.) Using a model I created using a waffle ball, permanent marker, and a flashlight, we talked about where they were located and how they worked.  Once the rods and rhodopsin have adjusted to the dark and become active, some humans can see in the dark as well as owls or lynx.
-Tested our color vision at night.  I distributed Skittles.  The kids guessed the color of Skittle they were given then ate the Skittle to see if they'd predicted correctly.  Color vision is delegated to the cones and is therefore less accurate in the dark.
-Tested our sense of smell at night.  Our sense of small is oftentimes sharper at night due to increased humidity in the air and decreased reliance on sight.  The kids all smelled the contents of containers I brought (of hot chocolate mix and cinnamon) then as a group guessed what they were smelling.
-Listened to the "pirate eye-patch" story.  Variations of this story are often used on night hikes.  The key is that everyone has to cover one eye before you begin and promise to leave their "eye patch" on during the entire story.  Light a candle while you tell your story.  In the story make eye patches a key aspect of pirates seeing in the dark.  In my story a female pirate names Helga uses the technique to lead her crew.  The important part is that you reveal the secret of the eye patch at the end of the story, then blow out the candle, and have the kids remove their eye patches.  In one eye the rods will be active and adjusted to the dark, in the other the cones will be active.  They'll be able to blink back and forth and see the difference.
-Ate Wintergreen lifesavers.  I had everyone partner up and chew with their mouths open in order to see the triboluminescence, then I explained the science.