Smartphones are a great technology. We need them every day. They have some secrets. One is on the new iPhone. It can measure someone's height. You just point your phone camera at someone and an app gives you their height. The person you are measuring must stand in front of the camera from head to toe. You can measure your own height in a mirror, but this is not so accurate. The new app could end arguments about who is the tallest.

The app is called Measure. It uses a special sensor that is inside the camera. The sensor uses LiDAR technology. This is "light imaging, detection, and ranging". LiDAR is used to make digital 3D models of the Earth. It measures a person's height by bouncing light off them. When the light returns to the sensor, the app calculates the person's height. A website joked that the app, "isn't as cool as drawing lines on a door" to find someone's height.