When a magnifying glass is held over a piece of paper at a distance equal to its focal length, the sun’s rays falling on the lens converge at a point that lies somewhere on the paper. Thus, solar ...

Burning things with a magnifying glass is one of the first scientific experiments many of us can remember trying when we were younger. Focusing the sun's rays on a piece of paper (or, if you were ...

Open the app, which has a magnifying glass in its icon. With the help of the slider at the bottom, zoom in or out on a piece of text on paper using the rear cameras on your iPhone.