The Standing Waves in a Pipe model displays the displacement and pressure waves for a standing wave in a pipe. The pipe can be closed on both ends, on one end, or open on both ends. The number of nodes in the standing waves can be changed via a slider. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting “Open Ejs Model” from the pop-up menu item. The Standing Waves in a Pipe model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ehu_waves_pipe.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for wave motion are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.