Curriculum Tie:

• Mathematics
  3rd Grade
  Standard 4
  Objective 2
• Mathematics
  3rd Grade
  Standard 5
  Objective 1

Summary:
Students will complete several activities to learn about gravity.

Main Curriculum Tie:
Mathematics - 3rd Grade
Standard 4 Objective 1
Select and use appropriate tools and units to estimate and measure length, weight, capacity, time, and perimeter of two-dimensional figures.

Materials:
Hang in There

• String
• Paper clips or washers
• Rulers

Tilt-a-Box

• Water
• Variety of water containers

Galileo's Marble Chute

• Cardboard tube
• Thin cardboard
• Tape
• Large marble

Can Drop

• 3-4 foot board
• Small cans (with contents still inside for weight)
• Several bricks, 2 x 4s or textbooks (the same size)
• Tape measures

Marble Drop

• Cardboard paper towel tube
• Soft modeling clay
• Steel balls or marbles
  

Weighing in On Gravity

• Large book
• Pencil
• Yogurt cups
• String
• Paper clips
• Rubber band
• Yardstick
• Washers
• Variety of small objects that will fit in the yogurt cup (e.g., erasers, pencils, marbles, coins, pebbles, etc.)
• Spring scales
• Experiment Log

Note: an alternative to a rubber band would be a small spring such as found inside a pen.

Additional Resources

Book

• The Science Book of Gravity, by Neil Ardley; ISBN 0-15-200621-4
• Max Goes to the Moon, by Jeffrey Bennett; ISBN 0-97-218190-3
• I Fall Down, by Vicki Cobb; ISBN 0-688-17843-X
• How Can I Experiment with Gravity?, by Cindy Dalton, & Teresa Sikora; ISBN 1-58952-013-0
• Gravity, by John Farndon; ISBN 0-7614-1340-5
• Investigate and Discover Forces and Machines, by Robert Gardner; ISBN 0-671-69046-9
• Waking Upside Down, by Philip Heckman; ISBN 0-689-31930-4
• Gravity: The Universal Force, by Don Nardo; ISBN 1-56-006204-5
• Toy Lab, by Michael Ross; ISBN 0-87-614456-3
• The Science of Gravity, by John Stinger; ISBN 0-7398-1323-4
• Zero Gravity, by Gloria Skurznski; ISBN 0-02-782925-1
• Experiments with Gravity, by Salvatore Tocci; ISBN 0-516-22513-8
• Gravity, by Janice VanCleave; ISBN 0-471-55050-7
• Physics for Every Kid, by Janice VanCleave; ISBN 0-471-52505-7
• Zero Prep for Beginners: Ready-to-Go Activities for the Language Classroom, by Laurel Pollard, Natalie Hess, & Jan Herron; ISBN 1-882483-82-0
• Creating Creative Curriculum: Focus: Science, by Anne Crabbe; ISBN B0006OWQVQ

Videos

• Gravity, by Bill Nye (Disney Educational Productions, 1-800-295-5010, http://dep.disney.go.com/educational/index); Product ID: VHS P#68A76VL00, DVD P#77C17VL00

www.dragonflytv.org
www.nsta.org
www.sciencenetlinks.com
http://wings.avkids.com/index.html
http://teach-nology.com/web_tools/work_sheets/

Attachments

• experiment_log.pdf
  

Background For Teachers:
Gravity is the force that keeps us on Earth. It is what makes things fall to the ground and rivers flow downhill. It is what keeps the moon circling our planet and all of the planets circling the sun. Gravity, or “gravitation,” is the universal force of attraction that tries to pull every piece of matter together. Every object in the Universe, no matter how small, has its own gravitational pull. The strength of this pull depends on the objects’ mass or amount of matter it has. Earth has a stronger pull than the moon because it is larger and has more mass.

Properties of gravity that third graders will learn in this unit:

• Gravity pulls all objects in the same direction—toward Earth.
• The amount of incline of a hill (how steep it is) changes the speed of a moving object.
• Heavier objects require more force to overcome gravity (and be lifted up) than lighter ones. Weight is the measure of that force.

Intended Learning Outcomes:
1. Use Science Process and Thinking Skills
4. Communicate Effectively Using Science Language and Reasoning

Instructional Procedures:
Invitation to Learn
Drop a large book or other object on the floor (the larger it is the more dramatic it will be). Ask why it landed on the floor? Once you let go of the book, why did it not stay in the air? Why did it move by itself without being touched? Lead the class to the idea that gravity made it fall. Say that gravity is a force. Review the definition of force from Standard III (a push or a pull). Ask whether gravity is a push or a pull. (pull)

Complete a K-W-L chart. Ask the students what they know about gravity. Write their statements under the Know column. Accept all comments—even incorrect ones. Later they will have an opportunity to correct any misconceptions and errors. Before each experiment, write the questions to be answered in the what I Want to know column. Add any questions the students have and questions you might elicit during discussions. As you work through the unit, refer back to this chart asking the students if there are any statements in the Know column that they want to change. These new statements will be written in the what I Learned column.

Instructional Procedures

Hang in There—Does gravity always pull objects toward Earth?

1. Have the students cut a 12-inch piece of string. Tie one end to a paper clip or washer. Tie the other end to a ruler. Tape the string on the ruler so it does not slide.
2. Hold the ruler parallel to the floor. Tilt one end of the ruler. Notice the direction of the clip. Hold the ruler perpendicular to the ground. Notice the direction the clip is hanging. The clip always hangs straight down. Earth’s gravity is a force that always pulls an object downward toward Earth.

Math extension: Instruct students to place their ruler on their desk so it forms an acute, obtuse, and right angle. The angles change—what about the direction of the string?

Discussion: Look around the school, playground, and your home. What objects do you see hanging down (swings, tetherball, mobiles, clothes on hangers, etc.)? What could be some problems or how could your life be different if gravity did not pull all of these objects straight down?

Tilt-a-Box: How does gravity affect water?

1. Think about rain drops. If there is no wind, what direction do rain drops always fall? (Students could make rain drops with pipettes and/or spray bottles and observe that the drops always fall straight down.)
2. Ask: Do water levels always stay parallel to the ground? Can it stand at an angle? Fill a shoebox-size plastic storage box half full of water. Have students measure the distance from the water level at both ends of the box to the table. Then tip the box by placing in on a block, pencil box, etc. Measure the level at both ends again. Students will see that the water level stays parallel to the table. (Tip: Have a student hold one ruler on the side of the box along the water line. It will make it easier for them to observe that the water level is still parallel to the table.)

Discussion: Ask students to explain how this demonstrates that gravity pulls all objects toward Earth. What other experiments could you design to show that gravity pulls on liquids. (Could make Jell-o or pudding. Pour into clear glasses or bowls. Prop the bowl at an angle in the refrigerator.)

Gravity causes objects to roll down inclined surfaces. The steeper the incline is, the faster the object will roll.

The activity, Galileo’s Marble Chute, is based on a chute Galileo created to test his theory that gravity causes falling objects to move faster. Since he did not have a stopwatch, he designed a water clock to measure the time it took the ball to travel through each chute.

Galileo’s Marble Chute: How does the incline of a hill affect the speed of an object?

1. Ask the students if they like to go sledding or tobogganing. Ask them to describe where the best places are to go sledding. Where is the nearest place you can get a good ride? What kind of hill makes you go faster?
2. Ask: Does the incline, or how steep a hill is, affect the motion of an object or how fast you can go?
3. Cut the tube in half lengthwise. Tape the two ends of the halves together to form a long chute.
4. Make marks every 6 inches. Cut a short slot on both sides of the chute at each mark.
5. Cut flaps from the thin cardboard. The curved section should match the inside of the tube.
6. Slide the flaps into the slots to make a series of gates. Slightly angle the flaps the same way.
7. Prop one end of the chute up on a pile of books. Test the marble to make sure none of the gates stick. When the marble rolls smoothly down the chute, you are ready to start the test. As the marble rolls down the chute, you should hear the gates clicking at shorter intervals. If you are having trouble hearing a difference, try experimenting with a lower slope. Also, the longer the chute is, the easier it is to hear the acceleration of the marble.

Explanations of new concepts should be presented in different ways. Also, students should be provided with several opportunities to apply what they have learned to new situations. This reinforces students’ new understanding (Barton, 2001).

The following activities reinforce the Hang in There activity. They also provide students with opportunities to explore the results of the idea that objects roll faster down steeper inclines as gravity pulls them toward Earth.

Can Drop

1. Place one end of the board up on a brick, 2” x 4”, or book.
2. Place a small can (such as a tomato paste can) on the board and let it roll down the inclined plane.
3. Measure how far it traveled past the end of the board.
4. Add another brick or book. Roll the can down the incline plane. Repeat several times—adding another brick or book each time to increase the steepness of the incline.
5. Have the students draw a chart in their journals to show the results.
6. Discuss with the students how they know that the can is picking up speed. What is the evidence? Make comparisons with other events that show that faster objects travel further (e.g., punting vs. trying to hit a home run in baseball) compare the difference in the amount of force applied.

Marble Drop

1. Shape the modeling clay into a thick, flat circle or rectangle shape (or choose another geometric shape the students are learning in math). Place on the tray next to the table.
2. Place the tube perpendicular to the edge of the table. Lift one end of the tube 1” up to form an incline. Roll a marble through the tube so it drops into the clay. Lift the tube up another inch, move the clay slightly to one side and roll the marble through the tube again. Lift the tube 3”, move the clay and roll the marble again.
3. Compare the depth of the three holes.

Problem solving opportunity: The ruler is probably too small to fit in the dent. Ask the students how they could measure accurately? (Put a pencil in the dent, mark the depth with another pencil, then measure with the ruler.)

Discussion: Ask the students to explain how this experiment demonstrates the concept the steeper the incline of the hill, the faster an object travels. Have them think of other objects that might land differently if the incline hill is steeper (e.g., what would be the condition of an egg rolling down a shallow incline vs. a steep incline?).

Help the students come up with other questions and add them to the K-W-L chart.

Heavier objects require more force than lighter ones to overcome gravity. That force is expressed as weight and can be measured using scales.

Weighing in On Gravity: Does it take more force to lift heavier objects?

1. Hold up a large book and a pencil. Ask which one would require more force to lift up. We can find out how much force it takes for each of these objects to overcome gravity by measuring their weight.
2. Scales tell us how much something weighs or how much force gravity is pulling on it. You are going to make your own scale to see how much force it takes to lift objects and overcome gravity.
3. Make three holes just below the rim of the yogurt container. Thread strings through each hole and tie knots. Tie the other ends together and tie them onto the end of the rubber band.
4. Hook the other end of the rubber band through a paper clip. Tape the paper clip to the zero end of the yard stick.
5. One student stands the yardstick on the floor and holds it in a vertical position.
6. Using the Experiment Log, record the point on the yardstick where the rubber band meets the string handle. This is the measuring point.
7. Place an object in the container and note how far down the yardstick the point stretches.
8. Compare the weight of a variety of objects.
9. Have students observe a spring scale. Compare the results of their homemade scale to the spring scale.
10. Have students weigh their objects using the spring scale and record their results in the third column of their chart. Discuss how their scales demonstrate or prove that gravity is pulling objects toward Earth.

Extensions:

• Teach techniques for making charts (using the ruler to measure and make the rows and columns even). Make a class chart showing the results of each experiment. Students can make their own in their journals.
• Learn how to draw cartoons. Have students draw a three to four frame cartoon showing what happens when objects roll down hills with increasingly steeper inclines.
• Give each group or student a large piece of butcher paper. Have them draw pictures of familiar objects that hang straight down because of gravity. Make a collage bulletin board.
• Have the students brainstorm all the ways gravity affects their lives. Record their ideas on chart paper.
• Working in small groups, have students brainstorm a list of the effects on astronauts living and working in near-zero gravity. (Give each student a colored pencil. Have them take turns being the scribe and writing their ideas on a large sheet of construction or butcher paper.)

Ask the students to identify and circle those effects that might be a problem. Then ask them to choose one of those problems and brainstorm solutions.

Instruct each group to choose their best solution. They are to prepare a short presentation for the rest of the class describing the problem and their solution.

Tell them that all group members must have an equal part in their presentation. This lesson is adapted from Creating Creative Curriculum: Focus: Science.

• Read Max Goes to the Moon. Extend the story. Max had a problem playing frisbee on the moon. What other games might have to be adapted to playing on a surface with little or no gravity?
• Work in small groups to assist English Language Learners.
• Draw pictures/diagrams. Assign partners who will help with labeling.
• Place new words on wall charts. (Snow, 1997)
• Concentric Circle Talk.
• Investigate Aristotle, DaVinci, and/or Newton and the important contributions they made to our understanding of gravity. There are engaging, readable books, as well as excellent Web sites, for student exploration. Prepare a presentation for the class (e.g., posters, brochures, power points, play, etc.).
• Have students prepare other experiments to demonstrate to the class. (Or they could be in charge of a learning center and work with individuals and small groups.)

Family Connections
Have students write a letter to family members explaining the concept they just learned. Include plans for an experiment they want to do at home (e.g., roll a tomato or egg down inclines of different heights). Have them draw a data chart that can be filled out at home.

Assessment Plan:
Assessment is most valuable if it is embedded within teaching. If we wait until the end of the instructional unit to assess understanding, valuable instructional opportunities are lost. “The 5E model of science instruction defines a sequence of inquiry-based science instruction that helps students focus on evidence and explanation. Each stage implies a unique purpose for assessment: diagnosing students’ incoming ideas, collecting information about students’ formative understanding, determining if students can apply their understanding to a new problem, and providing data for summative evaluation.” (Volkmann, 2003)

• Assessment Matrix
• Journals
• Individual dry erase boards—great for quick comprehension checks.
• Silent True/False
  Students write TRUE and FALSE on 2 cards. They listen for statements that are true or false and hold up the appropriate card.
• Group discussions—Pose a question. Small groups work out the answer. When all are satisfied, a spokesperson gives the group’s response.
• Concentric circle talk
  • Divide the class in half, giving all students a one or two.
  • Have all the “ones” stand in a circle facing outward.
  • Have all the “twos” stand in circle outside the first, facing inward.
  • Students will be facing a partner.
  • Tell the inner circle students (ones) that their job is to listen.
  • Tell the outside circle (twos) that their job is to speak for 30 seconds about _____ (e.g., describe an experiment that demonstrates objects roll down steep inclines faster than a gentle or more level incline).
  • After 30 seconds, tell the speakers to move one (or two or three) places to the left. This time they have to talk for one minute.
  • Move to the left again and speak.
  • Speakers and listeners change places. Repeat the above steps.
• Frayer Model Map
  This could be done as class or small group for practice on the subject of gravity. Have each student complete one at a later date as an individual assessment tool.
• Draw a three to four frame cartoon showing two objects dropping and water levels staying the same.
• Design other demonstrations to prove that the motion of objects change with the incline of a hill.
• Mini plays: Working in small groups, have students play the parts of different scientists explaining a scientific concept (e.g., inclines affect the speed of objects) and explaining how they can prove or demonstrate that concept.

Attachments

• assessment_matrix.pdf
  
• frayer_model.pdf
  

Bibliography:
Research Basis

Barton, M.L. & Jordan, D.L., (2001) Teaching Reading in Science. Association for Supervision and Curriculum Development.

This is a companion to Teaching Reading in the Content Areas. The authors review what the research says about reading and science. They review strategies of effective readers. The book includes a variety of graphic organizers to help students make sense of what they are reading and learning.

Kopnicek, B & Kopnicek, R. (1990). Teaching for Conceptual Change: Confronting Children’s Experience. Watson, Phi Delta Kappan, 680-684. http://www.exploratorium.edu/IFI/resources/teachingforconcept.html

This is an article on the barriers to changing children's misconceptions. The authors follow an elementary school teacher as she tries to help her students discover that sweaters and mittens do not generate heat. They review the research on reasons for students’ difficulty in changing misconceptions and present some strategies to assist with facilitating the change in mindset.

Snow, M.S., & Brinton, D.M. (1997). The Content-Based Classroom: Perspectives on Integrating Language and Content. White Plains, N.Y. Addison Wesley Longman.

This anthology features a variety of authors who have expertise in a wide range of settings and student populations. The text presents alternative models, research and assessment, and looks at the relationship between content-based instruction and other instructional approaches. It is filled with practical strategies and ideas.

Suping, S.M. (2003). Conceptual Change Among Students in Science. Retrieved January 5, 2005 from http://www.stemworks.org/digests/EDO-SE-03-03.pdf

The author identifies two types of naïve knowledge or prior conceptions that students bring with them. One of them, misconceptions, is highly resistant to change. The remainder of the article looks at the theoretical framework for conceptual change and presents four views of how it occurs. Four conditions to foster this change are described. Some suggestions for classroom instructional methods that promote conceptual change are briefly described. An extensive reference list aids those wanting more information.

Volkmann, M. & Abell, (2003) Seamless Assessment, Science & Children. 40(8), 41-45.

Elaborate, and evaluate. The authors show how they used a variety of strategies to assess their students during a unit on the moon. Strategies include: questionnaires, journals (which includes drawings and writings), puzzlers, building models, thought experiments, explanations essays, and poster presentations.

“The mark of a good assessment is that it not only provides information about what students know, but challenges students to develop deeper understanding.”

Author:
Utah LessonPlans

Created Date :
Dec 02 2005 10:26 AM