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10B Uniting the Heavens and Earth #1
Isaac Newton created a unified view of force and motion in which motion everywhere in the universe can be explained by the same few rules....
10B Uniting the Heavens and Earth #2
Newton's system was based on the concepts of mass, force, and acceleration, his three laws of motion relating them, and a physical law stating that the force of gravity between any two objects in the universe depends only upon their masses and the distance between them....
10B Uniting the Heavens and Earth #3
The Newtonian model made it possible to account for such diverse phenomena as tides, the orbits of planets and moons, the motion of falling objects, and the earth's equatorial bulge....
10B Uniting the Heavens and Earth #4
For several centuries, Newton's science was accepted without major changes because it explained so many different phenomena, could be used to predict many physical events (such as the appearance of Halley's comet), was mathematically sound, and had many practical applications....
10B Uniting the Heavens and Earth #5
Although overtaken in the 20th century by Einstein's relativity theory, Newton's ideas persist and are widely used....
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It’s Gravity
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Purpose
To develop students’ understanding of gravity and its critical role as the main mover of the universe.
Context
This activity will help students develop ideas about the enormous impact that gravity has on the universe—the shape and movement of the planets, the solar system, stars, and galaxies. Gravity is a very difficult concept for students to grasp. It is necessary for the complex ideas and insights about the earth's shape and gravity to develop gradually. At this level, getting the right answer is not as important as the critical thinking skills that students develop as they struggle to apply their mental models of the earth to real and imaginary situations. Misconceptions about the causes of gravity persist after traditional high-school physics instruction. High school is the time for all of the pieces to come together.
Concepts from physics and chemistry, insights from history, mathematical ways of thinking, and ideas about the role of technology in exploring the universe all contribute to an understanding of the character of the cosmos. In particular, the role of gravity in forming and maintaining planets, stars, and the solar system should become clear.
This lesson provides teachers with an opportunity to uncover students' existing ideas about gravity and to help them develop the foundation with which to understand the role it plays in the physical nature of the universe.
During the course of this and other related lessons, it is important to be aware of and address the many common misconceptions in studying and learning about gravity. Research has shown that it is common that misconceptions about the causes of gravity persist after traditional high-school physics instruction but can be overcome by specially designed instruction. The magnitude of the earth's gravitational force has also proven to be hard for students to conceptualize. For example, "even after a physics course, many high-school students believe that gravity increases with height above the earth's surface or are not sure whether the force of gravity would be greater on a lead ball than on a wooden ball of the same size." Understanding gravitational forces as interactions has proven difficult, too, particularly in "understanding that the magnitudes of the gravitational forces that two objects of different mass exert on each other are equal." (Benchmarks for Science Literacy, p. 340.)
Ideas in this lesson are also related to concepts found in the following benchmarks:
- 1A The Nature of Science: The Scientific World View (9-12) #1-3
- 4B The Physical Setting: The Earth (9-12) #1
- 10C Historical Perspectives: Relating Matter & Energy and Time & Space (9-12) #4
Planning Ahead
Materials:
Motivation
Before you begin, read the lesson plan The Earth's Shape and Gravity Part 2: What are your ideas about Gravity?, on the Adler Planetarium and Museum website, for background information. Students will complete the What Are Your Ideas About Gravity? worksheet, also from the Adler Planetarium and Museum website, as a warm-up activity. You will find the answers to the questions posed on the worksheet on the lesson page. The worksheet questions are numbered #5–#8, because they are part of a larger unit that is not included in this lesson. So as to minimize confusion, you may choose to change the question numbers to #1–#4 before you make copies for your students.
In addition, pay particular attention to question #6 on the worksheet. It makes references to "Question 3" from the series' Part 1 lesson. Please note—and inform your students—that the rocks in Question 3 "fell toward the center of the rocks."
As a way to properly check, orient, and intrigue students about gravity, ask them some thought-provoking questions like these:
- When you think of gravity, what comes to mind?
- Can anyone define gravity?
- How important do you think gravity is? Why?
(Accept all answers, but ask students support their views with explanations.)
After sparking interest and leaving these and other questions open, pass out the worksheet for students to complete individually. When finished, go over each question with the class, using the answers and insights provided on the "What are your ideas about Gravity?" lesson to guide your discussion. Depending on the level of your students and your teaching goals, you may choose to overlook the highly technical, formulaic details so as to not overload your students at this opening stage; basic answers should suffice.
The purpose of this activity is to help students develop ideas and identify examples of the enormous impact that gravity has on the universe—the shape and movement of the planets, solar system, stars, and galaxies.
In this second part of the warm up, distribute copies of the Web page Myths and Other Misconceptions. Have students read each statement aloud and encourage them to speculate and explain why each is erroneous before leading them to the correct answers. Also have them address the question of why some people might think these things are true, including members of the class who may have held these beliefs at one time.
At this point in the lesson, refer students to the It's Gravity student E-Sheet and ask them to read the introduction. The E-Sheet contains a link to a refresher on how gravity works. Advise your students that they can refer to that link throughout the lesson for more basic information about how gravity works.
Development
Now that students are oriented on the basic concepts and workings of gravity—particularly in terms of the central benchmark—have them use the It's Gravity student E-Sheet to go to the two primary resources for this lesson:
These two complementary sections from the Adler Planetarium are reviews of important historical developments and modern concepts in humankind's knowledge of the nature and workings of gravity.
Distribute the It's Gravity student sheet to the class before they go online. They will use this to take notes on important facts and insights about each period, figure, or concept that is discussed on the Web pages.
Students will complete the E-Sheet in two parts. After students have completed the History of Gravity section, go over the outlines briefly with the class using the notes provided on the It's Gravity teacher sheet.
Follow the same procedure for the second part of the lesson, where students use the online resource Modern Concepts.
When finished, have students begin a broader, interest-based discussion highlighting any critical developments or differences between the ideas of the two. Ask questions like the ones below to review, connect, and help your class further conceptualize what they have learned.
Ask students:
- Which historical figure do you think made the most important contribution to our understanding of gravity? Why?
- What do you find most surprising or interesting about gravity?
(Answers will vary. Ask students to support their views with evidence and examples.)
Assessment
As directed on the E-Sheet, students should write a brief, one-page essay in response to these questions:
What significant changes or differences do you notice between the historical and modern views of gravity? What do you think explains these differences? Do you think that our views of gravity may change in the future? Why might they change?
Extensions
This lesson may be followed by two Science NetLinks lessons that directly relate to and extend this subject matter: Foucault Pendulum and Black Holes.
Gravity and Black Holes: Guiding Questions features other sections in the Adler Planetarium curriculum that guide an inquiry-based approach to exploring the concepts of gravity, black holes, and other related concepts.
Created :10/27/2003
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