The COSEE-TEK DIY hydrophone project has evolved over the years with design improvements, refined methods, and increased collaboration with community colleges and the Marine Technology for Teachers and Students (MaTTS) program at University of Rhode Island.This 28 minute YouTube video describes all of the parts, tools and steps necessary to construct an affordable hydrophone (~$45) for use by teachers and students to explore underwater sounds. Click here to download the complimentary Material List and Fabrication Instructions (Version 4.0, Modified for MaTTS [6/25/2014]).