Fun to be had in the dark... We took our pack on a night hike during one of our regular meetings. BUT no flashlights allowed.. it was a great way to teach our cubs how the dark works.. One of the things we want to teach them is how their eyes adapt in the dark.. We also want them to understand , that when their eyes cannot see well, the rest of our senses go on overdrive.. Thats why we get more scared at night , we hear much better, and our sense of touch is very sensitive..
During a night hike, we did many activities with the pack.. Ended it with a hot chocolate.
Here are the highlights..
Guess that crayon colour
Give each cub a small scrap of paper and a crayon. Have them examine the crayon and determine its color. Tell them to write their answer on the piece of paper. Nine times out of ten they will be wrong. You can check to see who was right and who wasn't at the end of the hike back at the building. (The guess will be written in the color of the crayon.)
Explanation: Colors are nearly impossible for humans to see at night. We have two types of cells in our eyes called rods and cones. Rods are light sensitive cells helpful with seeing at night and cones allow for seeing in color. Humans have many more cone (color) cells than rod (night vision) cells; therefore, our color vision is great (during the day) and our night vision is poor. The only other animals that can see colors nearly as well as humans are diurnal (active during the day) birds. How do we know this? Many female birds choose their mates by the bright coloration of the males. Owls on the other hand, have mostly rods in their eyes so their low-light vision is very good.
The Brightest Match in the World
Tell the cubs that they are going to see the brightest match in the universe. Have them stand in a circle and cover one eye - it doesn't matter which one. (Tell them to cover it well so that no matter what, no light will enter that eye.) Students should leave the other eye open. Explain that you are going to light a match (or candle) and you want them to stare at the flame until you blow it out (10 - 15 seconds). Light the match. After you blow it out, have the students open and close each eye, switching from side to side. Ask students to describe any differences between what they can see with the eye that was covered and with the uncovered eye.
Explanation: Looking with what had been their covered eye, things should appear clearer and brighter. This is due to a chemical called rhodopsin. Our eyes produce this chemical in low-light situations to improve our night vision. In fact, within five minutes of being in the dark, we can see 1000 times better than when we initially went into the dark. When our eyes are exposed to light, all of the rhodopsin we have been producing is instantly destroyed, making our night vision poor again. Our eyes will not be able to produce the rhodopsin again until we are out of the light.
Lifesavers Sparks
Have the cubs form a circle. Pass one wintergreen lifesaver to each cub. Tell them to put the lifesaver in their mouth and chew with their mouths open! (Something they aren't allowed to do at home). Look in each other's mouths and observe what is happening.
Explanation: The lifesavers will spark. Why? When the sugar crystals break, they release a weak burst of ultra-violet energy. This energy excites the molecules of the wintergreen oil in the lifesavers and causes the oil to glow, or fluoresce. A similar effect can be seen when two pieces of quartz are struck together.
We have a cubcast on our site under the archive called: Kept in the dark..
Marc
www.knwcubs.com