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This science lesson is designed to be used with NOVA's two-hour
special "Galileo's Battle with the Heavens." The lesson is intended
for use in middle and high school classrooms.
Program Contents
NOVA explores the story of Galileo Galilei—his scientific
contributions, his clash with the Catholic Church, and his
correspondence with his convent daughter.
The program:
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provides an historical backdrop of 17th-century Italy, including
the spread of the bubonic plague, the role of the Inquisition,
and the influence of powerful court families.
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examines Galileo's astronomical discoveries, including four of
Jupiter's moons, sunspots, and the rotation of the Sun.
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highlights Galileo's role as founder of modern physics due to
his studies of motion and his experiments with inclined planes.
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shows Galileo's talent as an inventor with his improved
telescope design.
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tells of Galileo's correspondence with his illegitimate
daughter, Maria Celeste, who embraced the tenets of the Catholic
Church and became a nun.
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chronicles Galileo's clash with the Catholic Church following
publication of his Dialogue on the Two Chief World Systems, a
rhetorical masterpiece in support of the Copernican Sun-centered
system.
Before Watching
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Ask students what they know about Galileo Galilei. Where and
when did he live? (In Italy during the 16th and 17th centuries.)
What did he do? (He was considered the first truly modern
scientist because of his systematic observation of the real
world; his main contributions were in the fields of physics and
astronomy.) What happened to Galileo? (He was tried and found
guilty in 1633 by the Catholic Church's Inquisition for his
scientific beliefs.)
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Galileo made a number of scientific observations during his
lifetime. As they watch, have students take notes on his
contrbutions to science. Have students record what Galileo
studied, how he studied it, and any conclusions he drew.
After Watching
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Lead a discussion about Galileo. What was the most powerful
institution in Italy when Galileo lived? How did his discoveries
contradict beliefs of his time? What happens when discoveries
don't conform to the currently held belief system? How are
controversial science research efforts, like fetal tissue
research or cloning, handled by today's institutions, such as
government or religious organizations?
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Review students' notes about Galileo's scientific contributions.
What areas did he study? Which of his scientific discoveries
were the most revolutionary and why?
Activity Setup
Objective
To construct and evaluate graphs of the current sunspot cycle.
Materials for each student
Procedure
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Galileo studied sunspots, sketching pictures of the changing
pattern of spots on the Sun over time. In this activity,
students will study the nature of sunspot cycles.
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Lead a class discussion about sunspots. (See Activity Answer on
page 4 for detailed information on sunspots.)
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Following the discussion, give each student a copy of the
Plotting the Spots activity sheet.
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Review with students the definitions for solar minimum and solar
maximum. Have them study the sunspot cycles from 1900 to 1995 on
the graph found on the activity sheet. Ask students to look for
patterns in the data.
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Have students label the graph with an x for each solar maximum
and an m for each solar minimum. Have them estimate the year
when each cycle started and when it ended, calculate the length
of each cycle, and calculate the average length for the nine
cycles shown on the graph. Discuss their results. Be flexible
with the accuracy of reading the years of solar maximum and
minimum. The average should be approximately 11 years.
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Provide students with graph paper. Have them graph the data for
Solar Cycle 23. If using 5-quadrille paper, students will each
require three sheets; if using 10-quadrille, students will
require two sheets.
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When students' graphs are complete, discuss their results using
the questions on the activity sheet. You might want to make an
overhead copy of the graphs to facilitate the discussion.
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As an extension, have students research whether the year 2000
solar sunspot maximum caused any significant disruptions in
communications on Earth. Were any abnormal auroras reported?
Were any satellites, Earth-bound communications, or power
systems influenced by the solar maximum? For more information,
see: www.exploratorium.edu/solarmax/news.html
Plotting the Spots
Sunspots are cooler areas on the Sun that appear as dark spots.
These spots tend to occur in cycles that start at the solar minimum
(when the fewest spots occur), reach their solar maximum (when the
most spots occur), and reduce again in number until the cycle begins
again. Can these spots and their cycles tell us anything? Do this
activity to find out.
Procedure
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Observe the following graph of the sunspot cycles from 1900 to
1995. List any patterns that you notice. How is each cycle
similar? How is each cycle different?
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Label the graph with an x for each solar maximum and an m for
each solar minimum.
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From the graph, estimate the year when each cycle started and
when it ended. Calculate the length of each cycle and the
average length for the nine cycles shown.
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Graph the data from Solar Cycle 23 below on your sheets of graph
paper.
Questions
Write your answers on a separate sheet of paper.
When did Solar Cycle 23 begin? -
Did Solar Cycle 23 reach its solar maximum? If so, when did this
occur?
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Based on the average you calculated for the other solar cycles,
when do you predict this cycle will end?
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Can you predict when the next solar maximum might occur? Explain
your prediction.
Activity Answer
Historical records show that sunspots may have been observed as dark
spots on the Sun at least 2,000 years ago. Ancient people might have
seen these dark spots when the Sun was low on the horizon and
partially obscured by clouds or mist, since it would have been
impossible to look directly at the bright Sun without damaging the
eyes. It was not until about 1610, following the invention of the
telescope, that Galileo and others began observing and writing about
the dark spots they observed.
Sunspots are cooler areas on the Sun that appear as dark spots.
While most of the visible surface of the Sun has a temperature of
about 5700°K, sunspots are only about 4,000°K. Though they
vary in size, most are larger in size than the diameter of Earth.
Scientists say sunspots would be expected to glow orange in the sky,
many times brighter than the full Moon, if pulled away from the Sun.
They theorize that the spots are the result of magnetic �elds. The
number of sunspots is cyclical, with periods of many sunspots (solar
maximum) and periods of fewer sunspots (solar minimum). Solar
flares, or explosions on the Sun, often occur near sunspots.
Students will notice the cyclical nature of the sunspot cycle. Each
cycle is similar in shape and lasts about the same amount of time.
The number of sunspots observed at solar maximum varies, however,
from a maximum of nearly 200 sunspots to a low of about 60 (sunspot
numbers are averaged monthly).
Students will have to estimate from the graph exactly the year and
month. The average will be approximately 11 years.
Solar Cycle 23 began about mid-1996, and reached solar minimum about
October 1996. Solar maximum occurred about mid-2000. The next solar
minimum is predicted to occur sometime about 2006 and peak sometime
about 2010. Predictions are based on approximate 11-year cycles with
solar maximum occurring on average a bit less than halfway through
each cycle.
Learning More
Drake, Stillman.
Galileo: A Very Short Introduction.
New York: Oxford Univ. Press, 2001.
Presents a short introduction to Galileo's life and achievements
focusing on his conflicts with theologians but supporting the
hypothesis that he was a zealot for, rather than against, the
Catholic Church.
MacLachlan, James.
Galileo Galilei: First Physicist.
New York: Oxford Univ. Press, 1997.
Contains a detailed chronology of Galileo's life and sidebars
explaining his scientific contributions.
Sobel, Dava.
Galileo's Daughter: A Historical Memoir of Science, Faith, and
Love.
New York: Walker and Co., 1999.
Presents a human picture of Galileo the scientist and Galileo the
father.
The Galileo Project of Rice University
es.rice.edu/ES/humsoc/Galileo/
Contains an illustrated biography of Galileo, translations of
letters from his daughter, information about other scientists of
his time, a portrait gallery, and links to other resources.
NOVA Online—Galileo's Battle for the Heavens
www.pbs.org/nova/galileo/
Learn all about Galileo, from his place in science to his
mistaken belief that Earth's daily rotation and its annual orbit
around the Sun triggered ocean tides. Includes online
activities.
Standards Connection
The "Plotting the Spots" activity aligns with the following National
Science Education Standards and Principles and Standards for School
Mathematics.
Grades 5-8
Science Standard D:
Earth and Space Science
Earth in the solar system
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Earth is the third planet from the Sun in a system that includes
the Moon, the Sun, eight other planets and their moons, and
smaller objects, such as asteroids and comets. The Sun, an
average star, is the central and largest part in the solar
system.
Mathematics Standard:
Data Analysis and Probability
Grades 9-12
Science Standard D:
Earth and Space Science
Energy in the earth system
Mathematics Standard:
Data Analysis and Probability
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