Final answer:
A magnifying glass usually contains a convex lens, while glasses could contain either convex or concave lenses depending on the vision correction needed. These lenses operate on the principle of the law of refraction, with focal lengths determined by their curvature and materials.
Step-by-step explanation:
The type of lens in a pair of glasses or a magnifying glass depends on their function. Glasses may have convex lenses if they are designed to correct farsightedness or concave lenses if they are designed to correct nearsightedness. A magnifying glass typically uses a convex lens, which is thicker at the center than at the edges, to converge light rays and produce a magnified image of objects.
When exploring the properties of lenses, the law of refraction, also known as Snell's law, is central to understanding how they form images. For instance, to investigate the properties of an eyeglass lens as a thin lens, one can look through it in both directions, observing the difference in image orientation and size. Similarly, filling a clear bottle with water changes its properties, turning it into a lens with a variable focal length that depends on the water depth, as the water alters the path of light through refraction.
To draw a sketch of a lens, one would draw a representation of the lens shape, labeling it as either convex or concave based on its curvature.