A convex lens can project an image onto a screen through the process of refraction. When light passes through a convex lens, it is refracted (or bent) towards the center of the lens. This refraction causes the light rays to converge or come together at a certain point called the focal point. When an object is placed on one side of the convex lens, the lens refracts the light rays coming from the object and forms a real, inverted, and diminished image on the other side. By placing a screen at the location where the image forms, the projected image can be observed and captured.
