In this unit, students begin to understand matter and its interactions. Students learn how to develop a model to describe that matter is made of particles too small to be seen. Students begin building their understanding of matter by observing phenomena. Students build on their background knowledge of solids, liquids, and gases to describe different phenomena and work together to find a solution. Students build on this background knowledge of states of matter throughout the unit using technology and hands-on activities to get a better understanding of matter and its properties. Students begin to understand scale and magnification with the opportunity to use microscopes and black lights in the classroom. By the end of the unit, students are able to design a model of an element from the periodic table and understand that matter in the element is made of particles too small to be seen.