The Reason Why The Apple Watch Has A Red Flashlight Feature

The Apple Watch doesn't have an LED camera flash so it lacks the traditional flashlight you get with the iPhone, but it has a creative feature that can still help. Its screen can light up to illuminate your surroundings.

A wearable flashlight (as opposed to a handheld one) frees up your hands for situations like riding your bike after sundown, unlocking a door with your hands full, or helping out in an emergency. It's convenient, accessible, and you have it on you at all times. You don't need to pull your phone out of your pocket or dig around for it in your bag.

To activate it, you can just tell Siri, "turn on the flashlight." You can also swipe up from the bottom to access the Action Center and tap the flashlight icon (via Apple Support). From there, you can switch to red or white light modes by swiping across. The white mode provides a standard flashlight, nothing remarkable about it, but the red flashlight is designed for preserving your vision in low light.

The red flashlight is less likely to attract attention or disturb others around you, like when it's dark and you're in a theater, camping, or reading. It's also why red flashlights are popular with astronomers and night photographers. You won't accidentally blind yourself or others while using it. The reason why is especially fascinating. Here's how it works.

Light is a wave with alternating peaks and troughs. The space between these peaks and troughs is the wavelength. Different colored lights have different wavelengths. Blue light has a short wavelength, red light has a longer wavelength. White light is made of every visible color and contains all of the corresponding wavelengths. To our eyes, light with a shorter wavelength is brighter and more intense. That's why the Apple Watch comes with two flashlight modes — white and red.

When you're in the dark for some time, your eyes adjust to it. This allows us to see better in low light. Our night vision is disrupted by white light because our eyes have adjusted to the darkness. They're far less sensitive to red light in the dark, so you can see your surroundings without drawing so much attention or losing your night vision.

The light's brightness can be adjusted or turned off entirely using the digital crown (via Apple). Be mindful of how long you use the flashlight because the feature can drain a lot of battery.