This lecture explores the ethical and societal challenges that arise in scientific research. Drawing on examples from biomedicine, nuclear physics, genetics, artificial intelligence, and research integrity, it discusses how scientific discoveries can create moral dilemmas related to the use of knowledge, experimentation on humans and animals, authorship, conflicts of interest, and the broader impact of science on society. The talk also addresses reproducibility, scientific misconduct, and the responsibilities of researchers in maintaining public trust while conducting rigorous and ethically responsible research.