Although science presents ethical challenges to society, little is known about the ways in which adults express ethical concerns in everyday science-related situations. This study analyzed the ethical expressions in 1079 reader comments to online news coverage of animal experimentation and climate change in Israel. Some forms of ethical concerns were expressed in many reader comments following animal experimentation (70%) and climate change (47%) coverage. Opposition to animal experimentation was primarily expressed emotionally, whereas comments supporting these experiments and complex stances towards them were mainly couched in ethical reasoning. Ethical expressions related to climate change primarily drew on ethical concepts. The importance of trust in scientific practice and institutions was evident in both issues. Formal ethics, as expressed by using ethical concepts or ethical reasoning, were found to be present in public discourse, suggesting it can serve as a foundation to enhance public engagement with bioethics.