Learning about Night Sight
The human eye operates a little differently at night than it does during the day. The human eye relies mainly on cones, a specific receptor cell within the eye, to see during the day, in that the cones bring information about color in the world around us. At night, however, the cones are not terribly useful, and the rods become our main way of seeing. The rods occupy the center part of the human eye and specialize in telling light from dark and in detecting motion. The eye has to adjust to low light however, and basically has to turn on the rods before they can see well at night and also open up the pupil to a wider dilation.
Demonstrate the importance of low light to night vision by gathering all of the campers together facing one candle, torch, or other small light source. Do not light the candle until instructing the campers to close their left eye, while living the right eye open and looking directly at the light source. The process of acclimation takes a number of minutes to work, so assure the campers that the results will be well worth the wait. After five minutes staring at the light source with one eye, put it out and instruct the campers to alternately open their left and right eyes. The eye that has been staring at the light should see nothing but darkness, but the eye that remained in darkness will be able to see much more clearly in comparison.
Next, show the campers how images can be quickly imprinted on the eyes. Borrow a powerful flashlight from a camper and stand in front of the group. Instruct the campers to close their eyes and open them only when given the signal. Explain that you will tell the campers to open their eyes, next draw a figure with the flashlight, and then the campers must immediately close their eyes after you turn off the flashlight. When the campers close their eyes, they should see the picture that you just drew emblazoned on their eyes for a few seconds. Ask the campers if they can identify the image. As you are painting with the flashlight, start with simple images like letters and numbers and progress to more complicated such as horses and trees.
Use these activities dealing with light to discuss Jesus as the light of the world. In the first activity, the main light almost blinds humans in the darkness, and in the same way, once we see the light of Jesus, little else compares. But inevitably, we have to be able to see our way in the dark sometimes, and even then it is Jesus’ light that shines on our way as our eyes adjust to see His light in a new setting.