Engaging children's interest, inspiring active exploration of materials, and fostering cooperation between children and adults is the best way to promote the construction of knowledge. Some popular early childhood activities can be expanded to provide experiences and time for children to build on their prior knowledge. This column discusses resources and science topics related to students in grades preK to 2. This month's issue discusses how students can observe the properties of matter and document changes as materials are mixed. Mixing two materials can be a starting point to extend children's exploration of matter and mixtures. By mixing liquid and solid materials in a scientific way, young children have fun, develop their reasoning skills, and learn more about the nature of science. In this article, the author presents an outdoor activity to observe the properties of matter and document changes as materials are mixed.