Science centers can engage students; accommodate different learning styles and individual interests; help students become independent and confident learners; and encourage social skills among students. In this article, the author worked with third-grade students as they completed activities at learning centers during a week-long unit on simple machines. The simple machines discussed in this article are levers and inclined planes. Each center was designed using the 6-E learning cycle--Engage, Explore, Explain, Extend, Evaluate, and "E-Search," the use of technology to enhance learning and teaching. Students completed the activities in pairs or in groups of three students, and they rotated through the centers until each group had completed all the centers. A whole-class "debriefing" concluded the center investigations each day. This provided opportunities for students in different small groups to share and discuss their observations and ideas--and opportunities for teachers to provide guidance through concept application. (Contains 2 figures, 8 resources and 4 online resources.)