Exposing children to STEM education from an early age increases their curiosity and interest in STEM careers. Thanks to STEM education, children learn by working like little scientists and putting forward their own scientific products. Based on this approach, the aim of this research is to raise awareness among preschool children about the concept of light that they encounter in daily life. The study was carried out with 20 children aged 60-72 months in a public school in the spring term of 2022-2023 in Turkey under the name of "STEM Activity in Preschool Education: Let's Discover the Light!". The STEM activity plan was designed by the researchers in accordance with the 5E model under the guidance of the preschool education curriculum and Next Generation Science Standards. During the activity, the steps of the 5E model were followed, allowing children to design their projects to discover light, make observations, and achieve learning objectives related to STEM education in the preschool period. In this context, the present activity is effective for preschool children to receive STEM education and reach the determined international standards.