In this activity, learners investigate visual perception as well as plan and conduct their own experiments. In "CLASS EXPERIMENT," learners discover how depth perception works by testing their ability to perform motor tasks with one eye or two eyes. In "TRY YOUR OWN EXPERIMENT," learners design experiments investigating visual illusions, such as shadow vs. figure, length of lines, or apparent size. They can investigate visual attention with "minimum difference tests." This lesson plan includes background information and guides for educators and learners.