This month, "The Early Years" is focusing on magnets. The predicting and testing students do in this month's activity also relate to "Science and Children's" theme this issue, teaching the nature of science. Magnets are typically included in early childhood science curriculums because they are irresistible to children. Also, understanding that magnets attract and repel each other and some other materials is part of the physical science content standard for grades K-4 (NRC 1996). But, unlike subjects of study such as seeds or worm segments, magnetic force is not visible. What can children learn from working with magnets? Aside from introducing magnetism, exploring magnets makes a good introduction to learning about the nature of science, especially because magnetic force is not visible. Approaching magnet play as investigation opens the door to learning about science. In the activity described in this article, students experience magnetic force in play, and then in a methodical way. Interweaving comments about how science is carried out with investigation into magnetic force is one way to introduce students to the nature of science. Throughout the activity or experiment, students can be reminded that good science means making observations, creatively testing the evidence, replicating the results, sharing them with others, and quite often revising theories.