As physics masters view this presentation, they learn how nuclear power is used in submarines. They use Google Maps to plot a course through the ocean and calculate the time required for surfacing and traveling. They learn about fission, gamma rays, critical mass, and exponential decay. In a second session, they continue to explore radioactive decay and perform calculations using half life. The direct instruction is followed by an activity demonstrating half life using small candies. This is a neat lesson for physics, physical science, or STEM classes.