Download Universal Gravitation and General Relativity

Physics
HS/Science
Unit: 05
Lesson: 01
Suggested Duration: 5 days
Universal Gravitation and General Relativity
Lesson Synopsis:
This lesson explores the development of Newton’s gravitational law and its application and the study of the historical
development of gravity concepts, including the formal basis and predictions of Einstein’s general theory of relativity.
Application of the theories will be a focus so students gain a deeper understanding of how planetary motion, satellite
orbits, tides, and motion near Earth are impacted. This unit provides opportunities to distinguish between
hypotheses, theories, and laws.
TEKS:
P.4
P.4F
P.5
P.5A
P.5B
Science concepts. The student knows and applies the laws governing motion in a variety of situations. The
student is expected to:
Identify and describe motion relative to different frames of reference. Supporting Standard
The student knows the nature of forces in the physical world. The student is expected to:
Research and describe the historical development of the concepts of gravitational, electromagnetic, weak
nuclear, and strong forces. Supporting Standard
Describe and calculate how the magnitude of the gravitational force between two objects depends on their
masses and the distance between their centers. Readiness Standard
Scientific Process TEKS:
P.2
P.2A
P.2B
P.2C
P.2D
P.2K
P.3
The student uses a systematic approach to answer scientific laboratory and field investigative questions.
The student is expected to:
Know the definition of science and understand that it has limitations, as specified in subsection (b)(2) of
this section.
Know that scientific hypotheses are tentative and testable statements that must be capable of being
supported or not supported by observational evidence. Hypotheses of durable explanatory power which
have been tested over a wide variety of conditions are incorporated into theories.
Know that scientific theories are based on natural and physical phenomena and are capable of being tested
by multiple independent researchers. Unlike hypotheses, scientific theories are well-established and highlyreliable explanations, but may be subject to change as new areas of science and new technologies are
developed.
Distinguish between scientific hypotheses and scientific theories.
Communicate valid conclusions supported by the data through various methods such as lab reports,
labeled drawings, graphic organizers, journals, summaries, oral reports, and technology-based reports.
The student uses critical thinking and scientific reasoning, and problem solving to make informed
decisions within and outside the classroom. The student is expected to:
P.3A
In all fields of science, analyze, evaluate, and critique scientific explanations by using empirical evidence,
logical reasoning, and experimental and observational testing, including examining all sides of scientific
evidence of those scientific explanations, so as to encourage critical thinking by the student.
P.3D
Explain the impacts of the scientific contributions of a variety of historical and contemporary scientists on
scientific thought and society.
Express and interpret relationships symbolically in accordance with accepted theories to make predictions
and solve problems mathematically, including problems requiring proportional reasoning and graphical
vector addition.
P.3F
GETTING READY FOR INSTRUCTION
Performance Indicator(s):
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Research and create a written report on the history of gravitational forces, including Einstein’s contributions. Use
calculations to describe how the magnitude of the gravitational force between two objects depends on their
masses and the distance between their centers. (P.2K; P.3D; P.5A, P.5B)
4D, 4I; 5G
Key Understandings and Guiding Questions:
•
The universal law of gravitation formulated by Newton states that every two objects in the universe with mass
are attracted to each other.
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Physics
HS/Science
Unit: 05 Lesson: 01
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— What is gravity?
— In what ways does gravity hold the universe together?
The history of gravity is essential to a complete understanding of its importance. Newton reasoned its general
properties, Cavendish measured it, and Einstein extended it to an integrated theory of space and time.
— Who are important scientists in explaining gravity, and what did they do?
— What does relativity have to do with gravity?
Vocabulary of Instruction:
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speed
orbit
satellite
tides
relativity
Kepler’s laws
space time continuum
theory
hypothesis
inertial property
orbital period
ellipse
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gravitation
centripetal acceleration
uniform circular motion
velocity
black hole
Materials:
Refer to Notes for Teacher section for materials.
Attachments:
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Handout: Newton and the Apple (1 per student)
Teacher Resource: Newton and the Apple KEY
Teacher Resource: Gravity Notes
Teacher Resource: Gravity, Projectile Motion, and Orbital Motion
Handout: Research Questions and Rules – Presentation (1 per student)
Teacher Resource: Research Questions and Rules – Presentation KEY
Handout: My Solar System Lab (1 per student)
Teacher Resource: My Solar System Lab KEY
Handout: Problems with Gravity (1 per student)
Teacher Resource: Problems with Gravity KEY
Resources and References:
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“The Apple and the Moon” video: http://www.learner.org/vod/vod_window.html?pid=555
Phet simulation - “My Solar System”: http://phet.colorado.edu/simulations/sims.php?sim=My_Solar_System
Advance Preparation:
1. Make certain that the software that is needed is installed.
2. Prepare attachment(s) as necessary.
Background Information:
Newton's three laws of motion and the universal law of gravity are landmark theories in classical physics. The universal
law of gravitation describes the weakest of the fundamental forces in nature, yet it is the force that holds the universe
together. The success of this law, in describing the motion of planets and stars, provides evidence that the laws of nature
on Earth are universal, describing events throughout the universe. The students will learn that near Earth's surface,
Newton’s gravitational law describes the gravitational attraction (weight) of objects to the Earth, but it is also the law that
describes gravity as the force keeping satellites, moons, planets, and galaxies from flying apart.
The historical development of ideas about gravity will begin with the legend of Newton’s falling apple and end with
Einstein’s general theory of relativity, where gravity bends light and slows the passing of time. In the extreme, Einstein’s
relativity predicts or accepts the possibility of science fiction-like entities of black holes, worm holes, and time travel. Since
Lesson 02 is largely a study of Einstein’s special theory of relativity, the discussion of Einstein continues into the next
lesson.
There are no inherent safety considerations for this lesson.
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Physics
HS/Science
Unit: 05 Lesson: 01
GETTING READY FOR INSTRUCTION SUPPLEMENTAL PLANNING DOCUMENT
Instructors are encouraged to supplement and substitute resources, materials, and activities to differentiate instruction to address the needs of learners.
The Exemplar Lessons are one approach to teaching and reaching the Performance Indicators and Specificity in the Instructional Focus
Document for this unit. Instructors are encouraged to create original lessons using the Content Creator in the Tools Tab located at the top of the page.
All originally authored lessons can be saved in the “My CSCOPE” Tab within the “My Content” area.
INSTRUCTIONAL PROCEDURES
Instructional Procedures
Notes for Teacher
ENGAGE – Introduction to Universal Gravitation
NOTE: 1 Day = 50 minutes
Suggested Day 1
Attachments:
• Handout: Newton and the Apple (1
per student)
• Video: “The Apple and the Moon”:
http://www.learner.org/vod/vod_wind
ow.html?pid=555
• Teacher Resource: Newton and
the Apple KEY
• Teacher Resource: Gravity Notes
• Teacher Resource: Gravity,
Projectile Motion, and Orbital
Motion
• Handout: Research Questions and
Rules – Presentation (1 per
student)
• Teacher Resource: Research
Questions and Rules –
Presentation KEY
1. Use the Handout: Newton and the Apple to focus the attention of the
students during the showing of the streaming video “The Apple and the
Moon” from the Mechanical Universe Series. The site for the video is
http://www.learner.org/vod/vod_window.html?pid=555. It is free for
streaming to your class, but it may be necessary to create a login account.
2. Have students take notes and listen for the answers to specific questions.
The answers could be used as a quick review of the concepts and to aid
the upcoming classroom discussion. This sheet is not to be used for
grading purposes.
3. After viewing the video,
Ask:
• What is the connection between tides, black holes, and planets
orbiting the Sun? Students should arrive at the idea that it is gravity.
• Is this the same gravity that causes things to fall on the Earth?
(Yes)
• Does gravity behave the same everywhere in the universe? Lead
students to the idea that gravity is the same here and in space and that
gravity laws are universal.
• What is gravity? What causes gravity to attract objects to each
other? Students should remember that mass is the cause of gravity.
• How do we define a straight line? Various answers work, such as
the shortest distance between points A & B, but point out a good
answer is often the path that light travels.
• Does gravity affect light? Leave this answer for the students to think
about or research, but the answer is: If strong enough, it bends its path
from the original path – normally, it does not.
• What is a black hole? (Region of space where gravity is so strong
that light cannot escape)
• If light cannot escape from a black hole, does that mean that light
has mass? (No)
• In what ways does gravity hold the universe together? Don’t dwell
on this question now, but use it as a lead-in to the discussion on
general relativity.
4. Facilitate a classroom discussion on gravity. A historical overview
approach is suggested, which will give some focus to student research
papers. The Teacher Resource: Gravity Notes will assist with classroom
discussion; the Teacher Resource: Gravity, Projectile Motion, and
Orbital Motion is a companion document to the notes.
5. Distribute the Handout: Research Questions and Rules – Presentation
and expectations for the research project. This will allow students to gather
more information about the historical contributions of scientists. Students
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Instructional Notes:
The Mechanical Universe series is
excellent, but the mathematics is often
calculus-based and is displayed quickly
in some videos. Preview the videos to
make sure they are appropriate for the
level of the students.
The purpose of the Engage activity is to
introduce this unit, assess prior
knowledge, and concentrate on
Newton’s law of gravitation. After a
series of questions and informal
discussion, Newton’s universal law of
gravitation is detailed in a classroom
discussion format and related to
material studied previously. Specific
questions are given for the students to
research and to prepare a report.
A possible outline of the “discussion” is
available as “Gravity Notes”, but the
Mechanical Universe video does an
excellent job of covering the same
ideas.
Notes on Research Questions:
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Physics
HS/Science
Unit: 05 Lesson: 01
Instructional Procedures
Notes for Teacher
will research individually, but will be assigned groups at a later time.
6. Review the research expectations with the students, and answer any
questions they may have about the project.
Student groups should be encouraged
to begin their research immediately. A
number of the questions are at least
partially answered in various sections of
the lesson, including the Day 1
discussion.
Misconception:
• Students may think that
gravitational force is the same on all
falling bodies.
STAAR Note:
The concepts and skills explored in
this lesson are addressing standards
associated with the STAAR Physics
assessment Reporting Category 1:
Force and Motion and Reporting
Category 2: Gravitational, Electrical,
Magnetic and Nuclear Forces.
EXPLORE – My Solar System
1.
After answering any questions from yesterday’s activities, announce that
today students will be conducting an exploration of Newton’s universal
gravitational law through the Phet simulation “My Solar System”.
2.
Divide the class into laboratory groups, and have them complete the
activities of the Handout: My Solar System Lab.
3.
Monitor student groups, and assist in completing the activities.
4.
Lead a post-lab discussion of the questions on the exploration activity at
the end of the period.
5.
Review the goals for the day, and remind students to work on their
research questions from the engagement activity.
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Suggested Day 2
Attachments:
• Handout: My Solar System Lab (1
per student)
• Teacher Resource: My Solar
System Lab KEY
Instructional Notes:
The purpose of today’s activities is to
gain experience with Newton’s universal
law of gravitation using the Phet
simulation “My Solar System” which is
found at this URL:
http://phet.colorado.edu/simulations/sim
s.php?sim=My_Solar_System
Additionally, students were to explore
the following:
• Newton’s gravity law properties
• Henry Cavendish was the first to
measure the force between two
objects and confirmed Newton’s
hypothesis.
• Some of Kepler’s law properties:
o Orbits can be elliptical.
o Lower orbiting objects travel
faster and have a shorter
period.
o The centripetal force for orbiting
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Physics
HS/Science
Unit: 05 Lesson: 01
Instructional Procedures
Notes for Teacher
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EXPLAIN – Problems with Gravity
1. Provide students with the Handout: Problems with Gravity.
2. Have students work in small groups on problems. Tell them they will be
sharing their methods for problem solving with the class after a specific
amount of work time.
3. Have student groups share the process they used to solve each problem
with the class.
satellites is provided by the
gravitational force.
The orbits of satellites look different
as viewed from different locations.
The velocity of a satellite in orbit
depends only upon the mass of the
object being orbited.
The gravitational pull is on both the
satellite and the body orbited.
Suggested Day 3
Attachments:
• Handout: Problems with Gravity (1
per student)
• Teacher Resource: Problems with
Gravity KEY
4. Provide further details when needed to support student explanations, and
clarify misconceptions or underdeveloped concepts.
Instructional Notes:
The purpose for the explanation activity
is to allow students opportunities to
apply concepts to real-world situations.
This practice problem solving activity
can be done with strong student
assistance in providing guidance.
ELABORATE – Research Questions
Suggested Day 4
1.
2.
3.
If you have not previously done so, provide students with the Handout:
Research Questions and Rules – Presentation from the Engage
activity. Answer any questions students may have about the project.
Divide students into small study or lab groups, and have them answer the
questions on the research document and put them into a form according
to the guidelines. Students should have been researching the answers to
the questions individually and are now compiling information with their
group members.
Monitor groups, and assist students in preparing the research reports.
Share any additional resources you might have to help them finish.
Materials:
• Internet connection for students and
computers
Attachments:
• Handout: Research Questions and
Rules – Presentation (1 per
student) (from previous activity)
• Teacher Resource: Research
Questions and Rules –
Presentation KEY (from previous
activity)
Misconceptions:
• Students may think that
gravitational force acts on one
object at a time.
• Students may think only large
objects have a gravitational force.
EVALUATE – Performance Indicator
Performance Indicator
• Research and create a written report on the history of gravitational
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Suggested Day 5
Attachments:
• Handout: Research Questions and
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Physics
HS/Science
Unit: 05 Lesson: 01
Instructional Procedures
Notes for Teacher
forces, including Einstein’s contributions. Use calculations to describe
how the magnitude of the gravitational force between two objects
depends on their masses and the distance between their centers.
(P.2K; P.3D; P.5A, P.5B)
4D, 4I; 5G
1.
Remind students of behavior expectations for presentations.
2.
Have student groups share their presentations with the class.
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Rules – Presentation (from
previous activity)
Teacher Resource: Research
Questions and Rules –
Presentation KEY (from previous
activity)
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