Quests and Discussions for Students, Episode 7 !Written by Ann Druyan

Produced by Cosmos Studios !Overview Episode 7, “The Clean Room,” is an exploration of science at its best and worst - and an example of how one person can change the world for everyone’s benefit, without ever committing a single act of destruction or violence. It’s also a powerful example of solving a classic scientific problem. !Grade Levels 6-12 !Episode Summary Interwoven throughout the episode is the little known but heroic story of “Pat,” Clair Patterson, an All-American grad student in geochemistry from Iowa. In the late 1950s, his supervisor gave him what seemed at the time to be a simple scientific task: use a mass spectrometer to measure the presence of certain radioactive elements in a piece of rock to determine the age of the Earth. It turned out to be anything but simple. Patterson’s unwavering commitment to this challenge resulted in the discovery of the true age of the Earth – and one of the greatest public health dangers in history.

You can’t do justice to this man’s story without going all the way back to a time long before the Earth existed - to when the elements were formed in the hearts of stars. The violent youth of the Earth effectively erased all traces of its beginnings. How to ever know its true age?

Our story takes us across the centuries of searching until Patterson learns of a foolproof but incredibly arduous way to calculate it. In the course of these Herculean efforts, Patterson stumbles on a great danger. No matter what it costs him he will not rest until he can avert it. As he struggles, he attracts a nemesis, a man who exemplifies the misuse of science.

!All rights reserved, Cosmos Studios. For distribution to FOX affiliates to accompany the original broadcast distribution of

COSMOS: A SpaceTime Odyssey.

!Discussion Topics

• Clair Patterson went looking for the age of the Earth and encountered a great danger. Scientist and great citizen that he was, he would not rest until the danger was averted. Similarly, Sherwood Rowland and Mario Molina stumbled on a danger to the ozone layer from chlorofluorocarbons while studying the atmosphere of Mars in the 1970s. Can you find another instance in which pure scientific research lead to the discovery of a hidden peril?

• The ancient Romans well knew that lead was toxic and yet, they used it widely in things with which they came into daily contact. Name five things today with which we could draw parallels.

• In this episode, various ways of determining the age of the Earth are explored. What are the pros and cons of each?

• Clair Patterson solved the mystery of the age of the Earth by ridding his laboratory of lead and testing a sample of an asteroid in a mass spectrometer. How did that give the answer?

• There is no such thing as a non-toxic level of lead in humans. But lead is by no means the only element that is harmful to people. Name 5 others (examples: plutonium, uranium, radium, mercury, cobalt)

All rights reserved, Cosmos Studios. For distribution to FOX affiliates to accompany the original broadcast distribution of COSMOS: A SpaceTime Odyssey.

• With lead, we saw how the neurons were fooled by the lead atoms and embraced them, leading to a variety of mental illnesses. Are there other dangerous atoms and molecules that masquerade as harmless counterparts? !!

Relevant Scenes from COSMOS • Act One: The Age of the Earth • Act Two: Young Clair Patterson • Act Three: Easy as Duck Soup • Act Four: They Died Screaming • Act Five: Where’s All That Lead Coming From? • Act Six: Nature Will Not Be Fooled

For a deeper dive, more subjects touched on in Episode 7: !• Stellar origin of iron

• Oxygen and carbon

• Formation of our solar system

• History of efforts to determine the age of the Earth

• Atomic clocks

• Nuclear transmutation

• Meteoritic lead

• Mass spectrometry

• Lead contamination

• Clair Patterson determines the actual age of the Earth

• Ancient Roman Saturnalia

• History of lead poisoning

• Physiological effects on humans

• Tetraethyl lead

• Clair Patterson’s campaign against leaded gasoline

All rights reserved, Cosmos Studios. For distribution to FOX affiliates to accompany the original broadcast distribution of COSMOS: A SpaceTime Odyssey.