Forces and Motion Box Block Plan

Lesson 1: Introduction to forces
Students complete an anticipation guide, using prior knowledge to predict whether statements like “A rock thrown in space will keep going forever” are true or false.  

Lesson 2: Types of forces (informal)
Given the definition of “force” as a push or a pull, students analyze common interactions (sitting on a chair, kicking a soccer ball, etc.) and identify pushes and pulls on them in everyday language.
Strategy: Productive questioning

Lesson 3: Friction lab
Before formally defining the term “friction,” students investigate its effects by measuring the force required to pull baby shoes.  Variables for the students to investigate: size of shoe, type of sole, type of flooring, weight in shoe, force required to start moving vs. force required to keep moving.  Students identify factors that increase or decrease the amount of force required to pull and speculate about reasons.  The term “friction” will be introduced at the end of the lab.
Strategy: Scaffolded inquiry

Lesson 4: Types of forces (formal)
Students work cooperatively to complete a graphic organizer of information on forces or related ideas: gravity, weight, friction, static friction, sliding friction, air resistance, tension, and compression.  Each student in the group will read about two forces, complete accompanying sections of the organizer, and teach the information to the other students.
Strategies: Productive questioning, cooperative learning, reciprocal teaching

Lesson 5: Identifying forces
Students identify forces acting on objects in pictures, drawing labeled arrows to show direction and approximate magnitude of force.  
Strategies: Productive questioning, cooperative learning

Lesson 6: Net force: Balanced and unbalanced forces (informal)
Students participate in a number of activities involving forces.  Groups will push an object in the same direction, then in opposite directions.  Students play tug-of-war with shoes on, then with one side with shoes on, one side in socks.  (We will borrow one of the small rooms off the gym for this activity.)  They sketch a diagram of each situation and label it with force arrows, adding a final arrow to demonstrate the overall force.  The term “net force” will be introduced at the end of the activity.
Strategy: Scaffolded inquiry

Lesson 7: Net force: Balanced and unbalanced forces (formal)
Students work cooperatively to complete a graphic organizer of information on balanced and unbalanced forces.  Pairs of students read about one topic and compile information, then teach it to the other pair.  Students work together to compare the types of forces.
Strategies: Productive questioning, cooperative learning, reciprocal teaching

Lesson 8: Assessment: Types of forces
Students take a quiz on vocabulary (force, net force, balanced/unbalanced forces, gravity, friction, tension, compression, mass, weight) and complete free-body diagrams, labeling the relevant forces with arrows.

Lesson 9: Inertia and Newton’s first law
Students perform two mini-experiments: flicking an index card out from on top of a cup so that a coin on the card falls into the cup, and pulling a piece of paper out from under a cup of water.  They speculate on why they can do so.  The tem “inertia” will be introduced, and students watch Eureka! videos on inertia and mass, summarize the information, and use it to explain the mini-experiments.
Strategies: Scaffolded inquiry, productive questioning, interactive video viewing

Lesson 10: Applying Newton’s first law
Students identify forces acting on a golf ball flying through the air, focusing on why it eventually falls to Earth and stops.  They draw a diagram of the situation, adding labeled force arrows.  They watch a video of astronauts hitting a golf ball on the moon, and before hearing the outcome, diagram the situation again, labeling force arrows, predicting what will happen and justifying their prediction.
Strategies: Productive questioning, interactive video viewing

Lesson 11: Newton’s second law
Remind students of the correlation between mass of baby shoe and force needed to move it.  Students watch and take notes on Eureka! videos on speed and acceleration, summarize the information, and use the equation F = m ∙ a to predict which would require more force to move: object with small mass vs. object with large mass, etc.  
Strategies: Productive questioning, interactive video viewing

Lesson 12: Applying Newton’s second law
Students use prior information about planetary mass to predict which planets have the strongest gravitational force and predict how it might affect activities on the planet.  They create posters comparing a favorite sport or activity on Earth versus on the moon or another planet.
Strategy: Authentic assessment

Lesson 13: Newton’s third law
Students use force sensors to generate graphs showing forces on each when they push the sensors together and when they pull the sensors apart.  After observing the equal magnitude and opposite direction, they read about Newton’s third law, restate in their own words, and identify/label force pairs on pictures.
Strategies: Scaffolded inquiry, productive questioning

Lesson 14: Applying Newton’s third law
Students write a paragraph addressing the following prompt: Newton’s third law of motion states that for every action, there is an equal and opposite reaction.  Imagine a horse and a cart.  If the horse pulls on the cart, and the cart pulls on the horse, why don’t the two forces cancel out?  They accompany the paragraph with an illustration with labeled forces, using different colors for forces on the horse and the cart.  

Lesson 15: Assessment: Newton’s laws
Students take a quiz on Newton’s laws, restating them and identifying which law is illustrated in a given situation.

Lesson 16: Assessment task: Self-propelled vehicle

• Day 1: Students examine and play with assorted examples of self-propelled vehicles.  As a group, they decide on the method of self-propulsion they will use for their vehicle and begin planning.
• Days 2-4: Students build, test, and refine their vehicles.  They sketch the free-body diagrams of the stationary and moving vehicle.
• Day 5: Students race vehicles as a class, collecting distance and time data to calculate average speed.
• Day 6: Students work on essay.

Strategy: Authentic assessment

Lesson 17: Reflection
Students revisit anticipation guide from the first day of the unit.  They use what they learned to decide whether the same statements are true or false, and justify their decisions with information they learned.
Strategy: Student reflection

3. Friction Lab

Objective
Given lab equipment, students will be able to measure force required to pull baby shoes and identify factors that make pulling easier or harder.

Relationship to big idea
Everything physical in the universe is affected by forces.  These forces cause (or stop) motion.  In this lesson, students gain experience with friction and identify some factors that affect the size of the friction force.

Contribution to student understanding
The lesson helps students understand how real-life conditions on Earth, such as the presence of air resistance and other forms of friction, make it difficult to observe Newton's first law.

Essential question
How does the motion of a rock thrown in outer space differ from the motion of a rock thrown on Earth?  On other planets?

Set
Students complete a bell work assignment comparing situations where you might slip and fall versus situations where you can walk safely.  (Socks on a wood floor vs. shoes on dry cement, for example.)

Input
Remind students that a force is a push or a pull.  Today's lab will explore factors that affect how slippery baby shoes are (by measuring how hard you have to pull on baby shoes to make them slide).  They will answer the questions, "What things make baby shoes more slippery?  What things make them less slippery?"

Remind students of the definition of "variable" - something that can change each time an experiment is done.  In this experiment, students will examine the effects of several variables on the force needed to pull a baby shoe:

• Shoe size
• Type of surface (floor vs. carpet vs. cement outside)
• Weight of shoe
• Sole of shoe
• Starting vs. continuing to pull

Tell students the unit used to measure force is called a Newton, abbreviated N.  The unit is named after Sir Isaac Newton, an important scientist we will learn more about later.

[After students complete the lab, explain "friction" as a force that stops or makes it harder for two things to slide past each other.  Distribute sandpaper - have students pull two pieces past each other.  Use rough surface of sandpaper as an analogy.]

Model
Demonstrate how to use force sensor to collect data.  Model collecting data and recording information on data sheet.

Check for understanding
Students summarize task in pairs.  Individual volunteers report task components to teacher; teacher lists tasks in order on board.

Guided practice
Students measure force for situations of their choosing and record data.

Students discuss results and group variables according to whether they make pulling easier or harder.

Closure
Teacher names variable (smooth sole on shoe, carpet, etc.).  Students confer with groups and check data, then chorally respond to indicate whether variable makes it harder or easier to pull a baby shoe.

Approaches and instructional strategies
Scaffolded inquiry: This is a level 2 (structured inquiry) activity.

Science for social justice: Many of my students are from large families and have young family members.  They can relate to choosing baby shoes that are unlikely to slip and therefore safe for a baby to wear.  The activity uses a familiar context to promote understanding of the abstract concept of friction.

Cooperative learning: Group members are assigned roles (materials manager, data recorder, tester, executive) which rotate with each test.  Groups work on demonstrating cooperative behaviors (take turns, use each other's names, encourage everyone to participate)

Productive questioning: As groups work, teacher asks students reasoning questions.  (What have you noticed about pulling shoes over carpet?  How many Newtons of force does it take to pull shoes on the floor?  How is adding more weight to the shoe like pulling it over carpet?  What would happen if we took weight out of the shoe?  Why do you think it's harder to pull the sneaker than the smooth-soled suede boot?)
 

4. Types of Forces

Objective
Given a textbook passage on forces, students will be able to organize the passage's information into a graphic organizer and teach the information to other students.

Relationship to big idea
Everything physical in the universe is affected by forces.  These forces cause (or stop) motion.  In this lesson, students learn the scientific names and description of some forces.

Contribution to student understanding
The lesson helps students understand how the combination of forces affects the motion of objects.

Essential question
How do multiple forces on an object affect the object's motion?

Set
Students complete a bell work assignment identifying descriptions of forces (dragging your shoe on the ground, an apple falling to the earth) as "friction" or "not friction," based on what they saw in the previous lesson (baby shoes lab).  

Input
Explain that the previous lesson's lab explored the force of friction.  Friction isn't the only type of force - any push or pull is a force, and many of them have scientific names.  The scientific names of the forces students will read about today are: gravity, weight, tension, compression, friction, static friction, sliding friction, and air resistance.  Students will each read about two forces, complete their section of the organizer, and report back to their group.

Model
Demonstrate how to fill out the chart for students, using different sections for each force.  Walk students through process of identifying key words for the section and locating them or synonyms in the text.  (For example, when searching for the direction of the force, students might look for the words "direction," or "acts in.")

Check for understanding
Students summarize task in pairs.  Individual volunteers report task components to teacher; teacher lists tasks in order on board.

Guided practice
Students complete organizer for first task in small pieces, guided by teacher.  ("Find the definition of your first force in the book.  Now, put it into your own words.  Draw a picture showing an example of the force or describing the force.")  Students complete remainder of items with their groups while teacher circulates, checking work.

Students summarize the information they read to members of their group.  Summary takes the form of one sentence per section - students receive a template to follow.  

• _____ is _____.
• I drew ____ because ____.
• _____ acts on _____ objects.
• The direction of _____ is _____.
• _____ is affected by _____.

("Gravity is a force pulling objects together.  I drew ___ because ___.  Gravity acts on all objects, even if they aren't touching.  The direction of gravity is toward the other object.  Gravity is affected by the mass of objects and their distance from each other.")  

Closure
Teacher reads definition of forces.  Students check their notes, confer with groups, and chorally report the type of force described.

Approaches and instructional strategies
Cooperative learning: Task uses positive resource independence.  Groups work on demonstrating cooperative behaviors (use each others names, listen accurately to what others are saying, critique ideas, not people).

Productive questioning: As students work, teacher asks individuals questions.  (How is your first force like your second force?  How are they different?  What happens to the force of gravity if you move the objects farther apart?  What would happen if there were no static friction?  What is your reason for that drawing?)

Reciprocal teaching for reading comprehension: Modeling of comprehension strategies

5. Identifying Forces

Objective
Given seven drawings depicting motion, students will be able to correctly identify, describe, and indicate direction and relative magnitude of three to five forces in each.

Relationship to big idea
Everything physical in the universe is affected by forces.  These forces cause (or stop) motion.  In this lesson, students identify specific examples of forces acting in various situations.

Contribution to student understanding
The lesson helps students understand how the combination of forces affects the motion of objects.

Essential question
How do multiple forces on an object affect the object's motion?

Set
Students complete a bell work assignment reviewing the definition of forces on previous lesson's graphic organizer.  They may use the organizer and/or book to complete the task.

Input
Read directions for task: Students need to identify the force described and draw an arrow showing its size and direction.  All of the forces described are also on their "Types of Forces" notes.

Model
Demonstrate example item for students.  Read description of each force and walk students through process of comparing description to definitions of forces on notes.  Model placement and size of arrows representing forces on diagram.

Check for understanding
On first item, read description and have students check description against definitions on notes.  Students share and defend answer with group, then class chorally responds to report appropriate force (compression).  Ask students if they have finished the task (no) and what to do next (draw arrow on diagram).  

Guided practice
Students complete item 1, working with their groups; review as a class.  Students chorally respond with names of forces described and individuals describe direction of arrow.  Students complete remainder of items with their groups while teacher circulates, checking work.

Closure
On a quarter-sheet of paper, students sketch a situation described by the teacher: You push in your chair to leave the room.  Students identify three forces acting on the chair in this situation and draw labeled arrows to show the direction.  The quarter-sheet is their ticket out the door.

Approaches and instructional strategies
Cooperative learning: Groups work on demonstrating cooperative behaviors (take turns, use each other's names, encourage everyone to participate)

Productive questioning: As groups work, teacher asks students reasoning questions.  (Why do you think the example describes ___ force?  Can you invent a rule to describe situations involving static friction?)

Forces and Motion - Assessment Ideas

Performance tasks:

• Other-worldly sports – Students create a poster illustrating how their favorite sport might look on a planet of their choosing, explaining how differences in gravity and atmosphere could affect the forces on players of the sport and sports equipment
• Newtonian vehicle – Design and build a self-propelling vehicle, including schematics showing the forces on the stationary and moving vehicle and a written explanation of how the vehicle demonstrates Newton’s laws

Other evidence:

• Quiz – Types of forces
• Quiz – Newton’s laws
• Prompt – Explain why a rock and a feather fall at the same rate on the moon, but not on Earth.  Explain why a golf ball hit on the moon flies farther than it would on Earth.
• Prompt – Newton’s third law of motion states that for every action, there is an equal and opposite reaction.  Imagine a horse and a cart.  If the horse pulls on the cart, and the cart pulls on the horse, why don’t the two forces cancel out?
• Skill check – Draw qualitative free-body diagrams showing forces on stationary and moving objects

Student self-assessment and reflection:

• Self-assess the other-worldly sports poster
• Self-assess Newtonian vehicle
• Reflect on original answers to pre-unit anticipation guide

Theoretical Overview

Theoretical Overview

Some activities in the unit are inquiry-based, beginning with
structured inquiry to introduce students to a topic and progressing to
a guided inquiry assessment task (Bell, Smetana & Binns, 2005). 
Others promote cooperative learning, with tasks designed to promote
positive interdependence and interpersonal skills while holding
students individually accountable for their work (Johnson, Johnson
& Holubec, 1994).  

In the unit, I try to connect the California standards on forces to
inquiry-based activities relevant to my student’s experiences, thus
expanding their ideas about the nature of science.  If, as I believe,
the goal of science education is improving the scientific literacy of
students, then learning scientific facts, while an important aspect of
science, is insufficient.  Although the body of information amassed by
scientists represents a significant part of science, lack of effective
instruction on scientific process can lead to students conflating facts
about science topics with the entirety of the subject of science.  True
scientific literacy requires an understanding of scientific processes. 
To that end, students must learn critical aspects of scientific
thought. 

Selby (2006) explained science as “processes used in a scientific
inquiry, and products (ideas, information, laws) of the inquiry (What
makes it science section, para. 1).  Tinker (1993) suggested teachers
deemphasize the content of science in favor of the processes used to
gain scientific knowledge, saying, “Involvement in real science takes
time away from the curriculum so carefully designed to cover all the
relevant topics (pg.2).”  The current framework of state-mandated tests
dictates the focus of the unit, but through it, I expect to improve
student’s inquiry skills and understanding of scientific inquiry.

By connecting activities within the unit to the real-life experiences
of my students, I hope to both strengthen science literacy and lessen
educational inequity.  Barton and Yang (2000) saw the curriculum and
structure of science classes as unwelcoming to inner-city students. 
Greater emphasis on the human aspects of scientific inquiry might
promote inclusiveness of students with diverse perspectives and
cultivate an atmosphere which values their contributions (Selby,
2006).  My goal is to build a classroom community that models for
students the collaborative nature of science, as well as to build
student awareness of relationships between science concepts and their
personal experiences.

Tinker (1993) suggested that an ideal curriculum closely approximates
the work of scientists; students identify topics of interest and pursue
investigations, thus constructing their own knowledge.  Constructed
knowledge is richer than knowledge gained from lecture due to the
variety of experiences a student must relate when constructing
understanding of a concept.  A constructivist method popularized by
Karplus utilizes the learning cycle, linking a specific exemplar of a
concept to the main idea, and then inviting the student to apply the
concept to a new example (as cited in Tinker, 1993).  The learning
cycle helps me balance experiment with theory.  In the unit, I tried to
provide students a hands-on experience with each concept before
formalizing it and applying the ideas to new situations.

Moving the focus of science teaching toward inquiry-based lessons
providing a rich array of experiences with science would improve
student preparation to supplement their understanding of science
through reading.  As Tinker (1993) related, students remember new
material in a familiar subject better than in an unfamiliar one.  Their
existing framework of experiences with the familiar subject helps
improve comprehension of the new information.  Based on this research,
I placed lessons using the textbook after lessons which provide
students a common experience with the concept in question.  By doing
so, I hope to increase the effectiveness of the textbook as a learning
tool.

A true understanding of scientific ideas is grounded in a thorough
comprehension of the nature of science and the concurrent ability to
evaluate information.  While I do not expect that my students will gain
such an understanding by the end of the unit, I believe it will help
them progress toward a more complete conception of the discipline of
science.

References
Barton, A., & Yang, K. (2000) The Culture of Power and Science Education: Learning from Miguel. Journal of Research in Science Teaching, 37(8), 871-879.
Bell, R., Smetana, L., & Binns, I. (2005). Simplifying Inquiry Instruction. The Science Teacher, 72(7), 30-33.
Berliner, D., & Casanova, U. (1996). Putting Research To Work In Your School. Thousand Oaks, CA: Corwin Press.
Johnson, D.W., Johnson, R.T, & Holubec, E.J. (1994). Essential Components of Cooperative Learning. In The New Circles of Learning: Cooperation in the Classroom and School. (pp. 25-35). Alexandria, VA: Association for Supervision and Curriculum Development.
Johnson, D.W., Johnson, R.T, & Holubec, E.J. (1994). Formal Cooperative Learning. In The New Circles of Learning: Cooperation in the Classroom and School. (pp. 36-48). Alexandria, VA: Association for Supervision and Curriculum Development.
Martens, M. L. (1999). Productive Questions: Tools for Supporting Constructivist Learning. Science and Children, 36(8), 24-27, 53.
Selby, C. C. (2006). What Makes It Science? Journal of College Science Teaching, 35(7). Retrieved September 27, 2008, from http://www.nsta.org/main/news/stories/college_science.php?news_story_ID=52262
Tinker, R. (1993). Thinking About Science. Concord, MA: The Concord Consortium.
Wiggins, G. & McTighe, J. (2005). Understanding by Design. Alexandria, VA: Association for Supervision and Curriculum Development.

Forces and Motion - Sources and Standards

California State Science Standards Grade 8 - Forces

Standard 2: Unbalanced forces cause changes in velocity.
2b: Students know when an object is subject to two or more forces at once, the result is the cumulative effect of all the forces.
2c: Students know when the forces on an object are balanced, the motion of the object does not change.
2d: Students know how to identify separately the two or more forces that are acting on a single static object, including gravity, elastic forces due to tension or compression in matter, and friction.
2e: Students know that when the forces on an object are unbalanced, the object will change its velocity (that is, it will speed up, slow down, or change direction).
2f: Students know the greater the mass of an object, the more force is needed to achieve the same rate of change in motion.