As nanotechnology continues to be a focus of intense academic and commercial research and development, researchers need to be aware of and carefully consider their ethical responsibilities. This talk will first provide a short summary of "ethics" and introduce a "harms-based" criterion for making ethical judgments. We will then briefly discuss four harm-based fundamental ethical responsibilities of scientists and engineers, the first of which is to not do anything that will cause harm or create an unreasonable risk of harm to others, or to the public welfare. Ethical issues can arise at three societal scales, from the micro-society of a lab, to the lab's interactions with social institutions, such as the technical press, and finally to the broader society at large. We will then explore three case studies, one for each societal scale, in order to illustrate how researchers can apply the fundamental responsibilities to make ethical decisions about specific situations. The last scenario will highlight the pressures that researchers can face in start-ups, where the corporate motto sometimes seems to be, "fake it until you make it." Finally, we will offer several takeaways that we hope will be helpful in fostering ethical practice in all phases of the research and innovation process.