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Galileo's DialogueGalileos-Dialogue

  • Subject: Space Science
  • |
  • Grade(s): 9-12
  • |
  • Duration: Two class periods

Lesson Plan Sections


Students will understand the following:
1. Galileo's conclusions about the position of Earth in the solar system raised objections from the Church.
2. Galileo lived at the beginning of a period in which scientific inquiry flourished.


For this lesson, you will need:
Recent magazine and newspaper articles on controversial advances in science
Audiotapes and videotapes of radio and television discussions about controversial scientific topics



Help students to appreciate the heightened emotions that scientists, on the one hand, and the Church, on the other hand, felt when Galileo published his theory about Earth's position. That is, bring home the conflict between science and tradition today. Elicit from students scientific breakthroughs that humans are experiencing or may shortly be experiencing—breakthroughs that some members of society think should not be carried out. Students should come up with some of the following controversial issues:

  • cloning of animals
  • cloning of humans
  • genetic reengineering, genetic screening
  • fertility treatments
  • further research into space
  • radiation of food
  • greatly extending the average life span
2. Break students into groups, and have each research one of the preceding issues or other similarly controversial ones. The research should expose students to both sides of the issue—arguments for proceeding with scientific inquiry or breakthroughs as well as arguments for not proceeding.
3. Once the research is complete, assign half of each group's members the role of scientists working in the field, asking for support for their work to continue. Assign the other half of the group to play the roles of skeptical government officials, media, and concerned citizens, all of whom think it is improper to continue this line of scientific research and development. Have the students face each other in a news conference called by the scientists, who have an announcement to make. The government officials, media, and concerned citizens should ask challenging questions of the scientists and make statements of their own. Assign one student from outside the group to act as moderator for the news conference, introducing the scientists and calling on the government officials, media, and citizens who have questions or comments.
4. The rest of the class, watching each news conference, should comment on which side has stronger arguments or makes a better case—the scientists or the challengers of the scientists.
5. Sum up the project by making sure students understand that strong arguments exist on both sides of each issue, that seldom does one side have all the answers.

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If the readability level of research materials is too high, you may want to modify this activity by summarizing for students the articles' thesis statements and arguments.

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Discussion Questions

1. Explain the significance of Galileo's observations of Jupiter and its moons, and evaluate Galileo's contributions to science and history.
2. Discuss how the Copernican system threatened Church doctrine, and why the Dialogue of Galileo—a devout Catholic—offended the Church.
3. Debate Galileo's decision to recant his heliocentric views. Do you consider this cowardice, or did Galileo have no choice? What would you have done in his situation?
4. Discuss why students of world history need to study Galileo, the Catholic Church and its Inquisition in order to understand the Scientific Revolution, the Protestant Reformation, and the subsequent Enlightenment (Age of Reason).

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Rate students' work on this activity as acceptable or unacceptable. Consider the following elements as you observe the participants in each group's news conference:
  • Familiarity with common arguments surrounding the issue
  • Ability to explain the arguments clearly
  • Courteous interaction with other students during research and the news conference

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A Letter to Galileo
After viewing the video, have students imagine they had just witnessed Galileo recant his views. Ask them to write a letter to Galileo, who is under house arrest, asking him the questions they would have wanted to put to him at the time. Then have students exchange letters, do further reading and research if necessary, and answer the letters as Galileo might have.

Renaissance Panel Discussion
Select students to participate in a panel discussion in the roles of Copernicus, Bacon, Kepler, Galileo, and Newton. Students will, of course, need to familiarize themselves with each person's biography and main accomplishments. A team of three moderators should ask the panelists to comment on issues such as the following:
  • how each panelist wants to be remembered
  • why each panelist thinks his accomplishment is so important
  • what each panelist predicts for the next one hundred years, the next five hundred years, and the next thousand years regarding his area of specialty


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Suggested Readings

Galileo against the philosophers in his Dialogue of Cecco di Ronchitti (1605) and Considerations of Alimberto Mauri (1606)
Galileo Galilei (1564-1642), Los Angeles, Zeitlin & Ver Brugge 1976
In English translations, with introductions and notes by Stillman Drake.

Galileo and the Universe
Steve Parker, New York, NY: Harper Collins, 1992
This book discusses the life and discoveries of Galileo, the sixteenth- and seventeenth-century mathematician, physicist, and astronomer who challenged ideas more than a thousand years old and changed the course of science.

Starry Messenger
Peter Sis, New York: Farrar Straus Giroux, 1996
This book describes the life and work of the courageous man who changed the way people saw the galaxy, by offering objective evidence that the Earth was not the fixed center of the universe.

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The Galileo Project, Homepage
The Galileo Project is a source of information on the life and work of Galileo Galilei and the science of his times. There are sections on Ptolemy, Copernicus, maps, instruments, and other materials that can be incorporated in the classroom setting.

Galileo Galilei
This site introduces you to a student of Galileo. He presents his works and his contributions to science. This site is filled with wonderful images and texts.

The Art of Renaissance Science: Galileo and Perspective
This site presents information on Galileo's theories of motion and mathematics. There is also a section on the inquisition and trial of Galileo.

NASA Ames Research Center: Galileo Probe
The Galileo Project is a NASA unmanned mission to explore Jupiter and its surrounding moons. This site contains information on the mission and the planet Jupiter. It also has an extensive multimedia library and educational resources.

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Click on any of the vocabulary words below to hear them pronounced and used in a sentence.

speaker    heresy
Definition: An opinion or doctrine contrary to church dogma.
Context: He was burnt here in this place of Flowers for heresy by the Inquisition, February the 17th, 1600.

speaker    blasphemy
Definition: The act of insulting or showing contempt or lack of reverence for God.
Context: "Blasphemy!" they said. The first blasphemy in the sky: the moon was not pure and white.

speaker    ecclesiastical
Definition: Of or relating to a church especially as an established institution.
Context: The conceived order included a kind of ecclesiastical geography in which hell was in the bowels of the earth.

speaker    doctrinal
Definition: Preoccupied with a principle or position in a branch of knowledge or system of belief; dogma.
Context: And this was a threat to the whole doctrinal basis of the Church's teachings on the sacraments, on the nature of the Church itself.

speaker    recant
Definition: To withdraw or repudiate (a statement or belief) formally and publicly.
Context: And he was to be publicly humiliated in the grand hall of Santa Maria Socra Minerva in Rome, where he was to recant.

speaker    apocalyptic
Definition: Forecasting the ultimate destiny of the world.
Context: What sort of book brings a man to torture, changes the world. Surely it is apocalyptic.

speaker    dogma
Definition: A doctrine or body of doctrines concerning faith or morals formally stated and authoritatively proclaimed by a church.
Context: The guard dogs of Church dogma.

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This lesson plan may be used to address the academic standards listed below. These standards are drawn from Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education: 2nd Edition and have been provided courtesy of theMid-continent Research for Education and Learningin Aurora, Colorado.
Grade level: 9-12
Subject area: world history
Understands how European society experienced political, economic, and cultural transformations in an age of global intercommunication between 1450 and 1750.
Understands features of the conflict between religious beliefs and scientific thought during the Scientific Revolution (e.g., the coexistence of the new scientific rationalism in 17th and 18th-century Europe with traditional learning and rituals; Galileo's ideas about the solar system, and why he hesitated to apply scriptural passages to science-related problems; the fundamental ideas of Descartes' "Discourse on Method," and the methods he used to ascertain the "truth").

Grade level: 9-12
Subject area: world history
Understands how European society experienced political, economic, and cultural transformations in an age of global intercommunication between 1450 and 1750.
Understands causes and the major political, social, and economic consequences of the religious wars in Europe in the 16th and 17th centuries, and the legacy of these wars in modern Europe.

Grade level: 9-12
Subject area: world history
Understands how European society experienced political, economic, and cultural transformations in an age of global intercommunication between 1450 and 1750.
Understands the role of the Enlightenment in shaping European society (e.g., the impact of Europe's growing knowledge of other regions on the development of concepts of universalism, tolerance, and world history; the connection between the Enlightenment and the Scientific Revolution, and arguments supporting the notion that one was dependent upon the other).

Grade level: 9-12
Subject area: science
Understands essential ideas about the composition and structure of the universe and the Earth's place in it.
Knows ways in which technology has increased our understanding of the universe (e.g., visual, radio, and x-ray telescopes collect information about the universe from electromagnetic waves; computers interpret vast amounts of data from space; space probes gather information from distant parts of the solar system; accelerators allow us to simulate conditions in the stars and in the early history of the universe).

Grade level: 9-12
Subject area: science
Understands the nature of scientific knowledge.
Understands how scientific knowledge changes and accumulates over time (e.g., all scientific knowledge is subject to change as new evidence becomes available; some scientific ideas are incomplete and opportunity exists in these areas for new advances; theories are continually tested, revised, and occasionally discarded).

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Lara Maupin, world history teacher and globetrotter, Thomas Jefferson High School for Science and Technology, Alexandria, Virginia.

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