Chemical exposures in the womb can lead to what biologists call organizational effects - that is, impacts on the developing child that are irreversible. How were developmental problems associated with chemical exposures during pregnancy first discovered? And how did these discoveries influence policy? With me to discuss chemicals and child development is Tracey Woodruff. Tracey is a professor in the Department of Epidemiology and Population Health at Stanford University, where she co-leads the UCSF/Stanford Environmental Research and Translation for Health Center. She is an expert on environmental pollution exposures and impacts on health, with a focus on pregnancy, infancy and childhood, and health equity. Tracey was elected to the National Academy of Medicine in recognition of her pioneering work advancing environmental health and reproductive justice.

The age of exploration altered the course of human history, but how did early explorers find their way? Calculating their latitude at sea was a relatively straightforward proposition, but calculating longitude presented a vexing problem. Given the big power competition for colonies, conquest, and riches, the search to discover an accurate means of assessing longitude became a scramble. A major piece of the puzzle lay in the accurate assessment of time on a rocking vessel, which tested the ingenuity of the most creative clock makers. With me to discuss the history of the technologies associated with the measurement of longitude is Emily Akkermans. Emily is the Curator of Time at Royal Museums Greenwich, which includes the Royal Observatory Greenwich. The observatory is Britain's oldest purpose-built scientific institution, and it just celebrated its 350th anniversary - which is the impetus for this episode. The observatory is the birthplace of modern astronomy and the home of Greenwich Mean Time and the Prime Meridian.

Today we explore the life and legacy of the physicist Niels Bohr through the reflections of his grandson Tomas Bohr. Tomas is an Emeritus Professor at the Technical University of Denmark. He studies fluid dynamics, biophysics, chaos, turbulence and statistical mechanics, and he has a long and distinguished career publishing in these fields. He is a member of the Royal Danish Academy of Sciences and Letters.

Often in the history of science, myths overrun scientific findings and take hold with such force that they are difficult or nearly impossible to dislodge from public understanding. Perhaps no example of this phenomenon is more pronounced than that of the societal collapse of Easter Island, also known as Rapa Nui. With us to unravel the myth from the science is Mike Pitts. Mike is a writer and broadcaster (a frequent voice on BBC radio), archaeologist (directing excavations at Stonehenge), and one-time museum curator. He has written for The Times, Telegraph, Sunday Times, Observer, and Guardian, and many magazines including New Scientist, Archaeology, and BBC History. He edited British Archaeology magazine for 20 years and has written books on topics ranging from the discovery of Richard III's grave to How to Build Stonehenge. His original research has been published in peer-reviewed journals such as Nature, World Archaeology, and Antiquity. He is a Fellow of the Society of Antiquaries.

The Science History Podcast, now in its 9th year, has spanned Trump's first term in office, four years of the Biden Administration, and a year of the second Trump Administration, not to mention a global pandemic, horrific wars around the world, and the emergence of AI. So now seems like the perfect moment for some levity. The master of musical satire, Tom Lehrer, passed away in 2025. Here is my celebration of Lehrer's ability to make us laugh during the even more tumultuous times of the Civil Rights era, the Vietnam War, the Cold War, and political assassinations and violent polarization.

Today's episode is a discussion on the history of PFAS, or forever chemicals, including their accidental development, incorporation into commercial products, concerns about health effects, and environmental contamination and remediation. My guest is Sharon Udasin. Sharon is a Colorado-based environmental journalist and author of Poisoning the Well: How Forever Chemicals Contaminated America. She was a Ted Scripps Fellow in Environmental Journalism at the University of Colorado Boulder in 2019-2020 and received a SEAL Environmental Journalism Award in 2023. A graduate of the University of Pennsylvania and Columbia Journalism School, she has reported for numerous publications over the past two decades — most recently for The Hill.

The weather has always been a critical element of the human experience - deadly during storms and droughts, sustaining when aligned with the harvest schedule, beautiful and frightening, and integrated into the myths and religions of all societies. How did a scientific understanding of the weather come about? Here to guide us on this question is Simon Winchester. Simon's articles and approximately 30 books range in topic from travel writing to politics, geography, biography, and science history. Simon is best known for his books The Professor and the Madman, The Men Who United the States, The Map That Changed the World, The Man Who Loved China, A Crack in the Edge of the World, and Krakatoa, all of which were New York Times bestsellers. In 2006, Simon was made an officer of the Order of the British Empire by Her Majesty Queen Elizabeth the II. Today we discuss Simon's new book about the weather entitled, The Breath of the Gods, published by HarperCollins.

In Episodes 10 and 11 of the Science History Podcast, I interviewed James Muller on the role that Winston Churchill played in the unparalleled advancement of science and technology during the first half of the 20th Century, particularly as it related to the two world wars. In today's episode, Jim returns to discuss Churchill and an earlier war fought in the Sudan at the end of the 19th Century. Jim is a Professor Emeritus at the University of Alaska Anchorage and one of the world's foremost authorities on Churchill. For more than a quarter century, Jim has chaired the Board of Academic Advisers of the International Churchill Society. He is the author of many works on Churchill, including edited and scholarly reprintings of Churchill's interwar books Thoughts and Adventures and Great Contemporaries. Today we discuss his remarkable new edition of the two-volume Churchill book The River War: An Historical Account of the Reconquest of the Soudan, published in 2021 by St. Augustine's Press, which won the Churchill Literary Award from the International Churchill Society. St. Augustine's Press also published Jim's 2024 scholarly edition of Churchill's book My Early Life, A Roving Commission.

Our health, and the health of wildlife, depends on a clean environment. Since the advent of the industrial revolution, our environment has suffered from waves of pollution as different technologies came to the fore, each with its own set of practical benefits and associated chemical waste. Perhaps the most insidious of these environmental pollutants is lead. With us to discuss the history of lead as an environmental contaminant is Bruce Lanphear. For over 30 years, Bruce has investigated how toxic chemicals harm human health, especially the health of children. His research helped shape U.S. federal standards for lead in air, water, and house dust, and played a key role in the landmark conclusion that no amount of lead is safe for children.

The year 2025 has seen the most aggressive moves ever by the US executive branch against scientific research as the Trump Administration has gutted federal science and regulatory agencies and cancelled billions of dollars in research grants that had already been awarded to universities. With me to discuss the Trump Administration attacks on university research is Claudia Polsky. Claudia is a clinical professor of law and the founding director of the Environmental Law Clinic at the University of California, Berkeley.