In this activity related to light and perception, learners use a pinhole in an index card as a magnifying glass to help their eye focus on a nearby object. Learners will also discover that because this magnifier limits the amount of light that reaches their eye from the object, the pinhole makes the object appear dimmer. Learners are encouraged to explore using pins and needles with different diameters to make different-sized holes in index cards to see how this affects the image. They can also try forming a pinhole by curling their index finger.