Final answer:
It typically takes around 15 minutes for eyes to adapt to darkness and achieve night vision, facilitating improved visibility in low-light conditions.
Step-by-step explanation:
Adapting to night vision is a process that the eyes undergo when moving from a well-lit area to a darker one. This adaptation involves the physiological changes in the pupils and the rods and cones within the eye. Initially, when you enter a dark environment, such as a dark movie theater, it's difficult to see anything because your pupils need time to open up to allow more light to enter.
After approximately 15 minutes, the pupils have dilated sufficiently, and the eyes have adjusted; this is when you start to see shapes and movements more clearly. This process relies on the rod cells in your retina, which are more sensitive to low light conditions than the cone cells that process color vision. Although the integration time for the eye to add light energy is just a fraction of a second, the overall adaptation to darkness takes longer. Modern equipment like night vision goggles can overcome this short integration time and provide visibility in very low-light conditions by using long exposure techniques.