How do you rate your vision when there is plenty of light? To test this, take an object from the bag and hold it in the light. How large were they when you just turned on the light? How large are they when the light is on for a while? Why do you think this change happens? Turn on the room’s bright light and quickly observe the pupils. Do you think anything special will happen to the pupil? In a moment you will switch on the light and immediately look at your volunteer’s pupils or your pupils in the mirror. Repeat previous step with another object from the bag. Can you and your volunteer see well enough to say what the object is? Can both of you identify the object’s color? Let’s test: Pick an object from the bag. 
How is your vision in the dark (also referred to as night vision)? Can you see anything and, if so, can you recognize items? Can you describe them accurately?
Allow your eyes to adjust to the dark for a few minutes. Put a few markers, pencils and pens in a bag, and bring it and your volunteer to a dark room. In this activity you will estimate the size of the pupils. The dark circle in the middle of the eye is the pupil. Look your volunteer in the eye or look at your eyes in a mirror. Before we start you need to know what the pupil of an eye is. Markers, pencils and pens of different colors and a bag to carry them in. Room with a bright light (such as an overhead light) that can also get dark (nearly pitch-black works best). 
Flashlight that shines red light (You can also hold a translucent red object such as a translucent red food container lid in front of the white flash to make it shine red light.). Because some nerve connections cross over to the other eye, both pupils contract in unison. This is the result of a nerve signal generated in the back of the eye triggering the muscles in the iris. Switch to bright light and the pupils automatically contract. In dim light the pupils dilate (open wider) so more light can enter. Its main function is to regulate the amount of light that enters the eye. The colored part around the pupil called the iris adjusts the size of the pupil. They appear black because light almost never escapes through them. The pupil is the opening in the middle of the front of the eye that allows light to enter. The brain then makes sense of the signals, giving us the experience of seeing. As a result signals zoom along the optic nerve to the brain. This light triggers light-sensitive cells in the retina at the back of the eye. 
Have you ever considered taking a nighttime nature walk? Would you wait until there is a full moon so you could benefit from sunlight reflected from the moon-or would you rather take a flashlight? Do you think trees would look black, green or gray in the dark? Try this activity to examine your night vision and prepare for your next nighttime adventure!
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