This paper describes a renal physiology review activity that can be completed during one class session. The activity is a tactile simulation in which colored beads represent various components of the blood, glomerular filtrate, tubular fluid, and interstitial fluid. Students simulate major functions of the nephron by moving beads between compartments represented by simple diagrams. The diagrams include the glomerulus and Bowman's capsule, proximal tubule with peritubular capillaries, and the loop of Henle with vasa recta. Students transport the beads along the nephron and, in each region, make decisions regarding what is transported, beginning with filtration and reabsorption in early cortical segments. In the medulla, students consider the functions of the descending versus ascending limbs in both the loop of Henle and the vasa recta. Here, the focus is on mechanisms of water and salt transport that set up and maintain the osmotic gradient in the medullary interstitium as well as concentrate and dilute the urine. As students proceed along the nephron they answer review questions. They are also given a short clinical scenario and asked to apply their knowledge of transport across membranes to predict the effects of loop diuretics on urine formation. Finally, a set of additional review questions is included that students can complete outside of class. This active learning approach to teaching renal physiology provides students the opportunity to develop higher-order cognitive skills as they move beyond rote memorization and basic understanding to application and evaluation.