There are six lessons in this month's unit. Lesson 44, "Force," deals with various types of pushes and pulls, including gravity and magnetism. Lesson 45, "Work," defines work as a push or pull that causes an object to move and discusses common units for measuring work. The lesson also uses the concept of work to describe walking and carrying a load, etc. Lesson 45 discusses common units for measuring work as well as the formula for calculating amount of work done. Lesson 46, "Speed," defines speed as the distance something travels in a unit of time. It discusses how speed is measured and uses the concept to describe the motion of cars and people walking, etc. Lesson 47, "Power," defines power as the time in which work can be done. It also discusses how power is calculated, a common measure of power, and uses the concept to describe the activity of horses and people running, etc. Lesson 48, "Simple Machines," discusses the inclined plane, wedge, lever, screw, wheel and axle, and pulley in terms of force, work, speed, and power. These machines are described as simple because they have few parts and are powered by humans. Lesson 49, "Simple Machines in Westward Expansion," calls for students to identify the principles of simple machines in the covered wagons, garden forks, shovels, etc. used by Americans who took part in Westward Expansion. All lessons include written or oral activities which use the presented information. Each lesson builds on the previous one. For this reason, the lessons should be used in the numerical order in which they are presented.
Fifth Grade - Science - Lesson 44 - Force
Use the term force (push or pull) as understood in physics to explain gravity and magnetism.
Discuss the following units for measuring force: pounds, newtons.
Sentence strip containing a definition of the concept of force: Force is a push or pull.
Sentence strip containing a definition of physics: Physics is the study of energy.
Sentence strip containing this statement: Like poles attract, unlike poles repel.
One hand-held magnetic compass per group of five students
One worksheet per student (optional)
Two bar magnets
Steel paper clip
Ardley, Neil. The Science Book of Gravity. San Diego: HBJ-Gulliver Books, 1992. This non- fiction picture book contains suggestions for independent activities related to gravity, including a version of the student demonstration suggested below, on page 8.
________ . The Science Book of Motion. San Diego: HBJ-Gulliver Books, 1992. This non-fiction picture book is about motion, a topic very closely related to force. Recommend it to your independent readers.
________ . Action Science: Force and Strength. New York: Franklin Watts, 1984. This book contains suggestions for carrying out a number of science activities related to force.
Recommend it to students who are interested in independent science activities.
Barret, Neil S. Picture Library: The Moon. London: Franklin Watts, 1985. This nonfiction picture book uses color photographs to discuss lunar visits. Recommend this book to students who are curious about how gravity is related to space travel.
Branley, Franklyn. What makes a Magnet? New York: HarperCollins, 1996. This nonfiction picture book explains the properties of magnets. Recommend it to your students.
Cobb, Vicki. Why Doesn't The Earth Fall Up? New York: Lodestar Books, 1988. This non- fiction picture book discusses questions related to gravity. The illustrations are by Ted Enik. Recommend it to your independent readers.
Couper, Heather and Nigel Henbest. Black Holes: A Journey to the Heart of a Black Hole and into One of the Mysteries of the Universe. New York: A DK Publishing Book, 1996. This is a picture book that discusses interesting aspects of gravity. Recommend it to your independent readers.
Jennings, Terry. Making Science Work: Weighing and Measuring. Austin-Raintree/Steck- Vaughn, 1996. Recommend this nonfiction picture book to independent readers who need to improve their understanding of measuring or weighing in science.
Kerrod, Robin. Science Alive: Moving Things. Morristown: Silver Burdett Press, 1987. This nonfiction picture book discusses forces. Recommend it to your students.
Lafferty, Peter. Eyewitness Science: Force and Motion. New York: DK, Inc., 1992. This nonfiction picture book discusses the forces that set things in motion. Recommend it to your independent readers.
Liem, Tik. Turning Kids On To Science in The Home Book 3: Forces and Motion. Chino Hills: Science Inquiry Enterprises, 1992. This book contains suggestions for doing activities on force, using materials found around the house. Page 6 contains a version of the student demonstration suggested below.
McTavish, Douglas. Pioneers of Science: Isaac Newton. New York: The Bookwright, Press, 1990. This picture book discusses the life of Isaac Newton, including his pioneering work in discovering gravity. Recommend it to advanced independent readers.
Parramon's Editorial Team. Super-charged Science Projects. Hauppauge: Barron's Educational
Series, 1994. This book contains suggestions for independent activities on magnetism. Recommend it to your students.
Scagell, Robin. Space Explained: A Beginner's Guide to the Universe. New York: Henry Holt and Company, 1996. Recommend this nonfiction picture book to independent readers who are interested in gravity and space.
Sipiera, Paul P. I Can Be a Physicist. Chicago: Children's Press, 1991. This is a picture book explaining what a physicist does. Recommend it to your independent readers.
Skurzynski, Gloria. Zero Gravity. New York: Bradbury Press, 1994. This nonfiction picture book discusses some common effects of gravity. Recommend it to your independent readers.
Ward, Alan. Project Science: Magnets and Electricity. New York: Franklin Watts, 1992. This picture book describes magnets in simple language and with the use of color pictures. Recommend it to your independent readers.
Valens, E.G. Motion. Cleveland: The World Publishing Company,
1965. The text and the photographs in this book use common examples of
motion to lead the students to ponder the laws of motion, a topic closely
related to force. Recommend this book to your advanced independent readers.
The photographs are by Berenice Abbott.
Hirsch, E. D., Jr. ed. What Your 5th Grader Needs to Know. New York: Doubleday, 1993. This reference contains a brief discussion of gravity.
Lafferty, Peter. More Science Projects: Electricity and Magnetism. New York: Marshall Cavendish, 1989. This books contains suggestions for carrying out science projects in magnetism.
Mandell, Muriel. Physics Experiments For Children. New York: Dover Publications, 1968. This reference contains suggestions for experiments in magnetism. Page 38 contains a version of the student demonstration suggested below.
VanCleave, Janice. Janice VanCleave's Physics For Every Kid: 101
Easy Experiments in Motion, Heat, Light, Machines, and Sound. New York:
John Wiley and Sons, 1991. This reference contains suggestions for experiments
in magnets, gravity, and motion. Page 72 contains a version of the student
demonstration suggested below.
For this lesson, students recall gravity, magnetism and the use of magnetic compasses from Second Grade Science and energy, mass, and matter from Fourth and Fifth Grades Science. Magnets are the subject of Lesson 110 and 111 in Reading Mastery 111. Gravity is the subject of Lessons 63 to 70 in Reading Mastery 1V.
force: push or pull
Fifth Grade - Science - Lesson 44 - Force
gravity: force that pulls objects toward each other
magnet: any substance that attracts iron
magnetic: material that is attracted by a magnet
magnetism: force of a magnet that makes it attract certain materials; invisible pull and push that can act across space and through nonmagnetic materials
magnetite: modern word for lodestone, or naturally occurring magnetic rock
motion: act or process of moving from one place to another
newton: unit of measurement of force, named after Sir Isaac Newton (1642-1727); A newton is the equivalent of .225 pounds.
nonmagnetic: materials that a magnet will not pull
physics: the study of energy
rest: not in motion
Start with this demonstration. In full view of the students, display a steel paper clip that is at rest. Ask: Is this paper clip at rest or in motion? (at rest) Ask: What does the expression "at rest" mean? (not in motion) Ask the students to observe while you place a bar magnet close enough to the steel paper clip that it is attracted to the magnet. Ask: Did the steel paper clip move or did it remain at rest? (moved) Write the words "motion" and "rest' on the board and explain that motion means movement and rest means no movement. Ask the students to identify the metal bar (magnet). Ask the students to identify that quality of the magnet which makes it attract the steel paper clip (magnetism). Ask the students to identify the class of objects, including the steel paper clip, which are attracted by magnets (magnetic). Write the terms "magnet," "magnetic," and "magnetism" on the board.
Ask: How do magnets affect magnetic objects? (attract them) Ask: What are nonmagnetic objects? (objects that are not attracted by magnets) Ask the students to identify some non-magnetic (fabric, plastic, wood, water) and magnetic objects (iron, steel). Ask: Are all metals magnetic? (no) Ask the students to identify some nonmagnetic metals (silver, gold, copper, aluminum). List these materials under two columns titled "magnetic" and "nonmagnetic." Ask: Do magnets occur in nature? (yes) Remind the students that there are rocks that act like magnets. Ask: What are these magnets called? (lodestones, magnetite) Write the words "lodestone" and "magnetite" on the board. Explain that magnetite is a modern name for lodestone. Ask: Does a magnet have to touch a magnetic object to pull it? (no) If students are not certain of this, quickly repeat the opening demonstration. Ask: Can a magnet attract a magnetic object if they are separated by a nonmagnetic object? (yes, depending on the thickness of the nonmagnetic object and on the strength of the magnet)
Remind the students that the pull of a magnet is stronger in two places. Ask: What are these places called? (poles, north pole, south pole) Explain that either pole will attract iron or steel. Quickly demonstrate this using the bar magnets and the steel paper clip. Now, identify the poles and place two north poles or two south poles together and have the magnets push each other away. Ask the students to comment on the direction of the movement in this case (push). Place two opposite poles of bar magnets close to each other and have the students observe and describe the reaction (pull). Write the words "push" and "pull" on the board. Explain that a push tends to increase the distance between two objects and a pull results in the two objects becoming closer to one another. Draw the students' attention to the sentence strip containing the statement: Like poles repel, unlike poles attract. Ask the students to suggest a simple word for repel (push) and one for attract (pull).
Ask the students to recall that one of the most important uses of magnets is in navigation, and invite them to identify the device in which they are used (magnetic compass). Show the students a magnetic compass and ask them to identify it by name and describe its use (to locate the earth's North Pole). Ask for volunteers to explain how a magnetic compass works. Tell the students that the earth works like a huge magnet with strong magnetic forces operating at the north and south poles. Have a student volunteer identify the North and South Poles on a globe (near top and bottom of map). Place the students in groups of five and supply a magnetic compass to each group. Point out the painted end of the needle, identify it as the north-seeking pole of a magnet, and explain that this needle reacts to the earth's magnetism so that it always comes to rest pointing toward the North Pole.
To demonstrate the workings of a magnetic compass, ask one student in each group to hold a compass in the palm of his or her hand and turn around while he or she, alo