Getting Your Bearings

Build Materials (For each team)

Required Materials for Activities 1, 2, 3

• Jar lid (from mayonnaise or similar container)
• 25 identically sized marbles (larger than depth of lid used)
• Book
• Section of carpet or rug 

Required Materials for the Challenge

• 100 Pencils
• Tape
• 25 Rubber bands

Testing Materials

• Desk or small table
• Section of carpet or rug

Materials

• Desk or small table
• Section of carpet or rug

Process

Teams test their designs by showing how they can move the desk/table 10 feet with only their index finger.

Design Challenge

You are a team of engineers working together to design a system using roller bearings to move one of your classroom desks, or a table, 10 feet. Limit the force you apply to make the desk or table move to what you can push using only your index finger.

Criteria

• Must move desk or table 10 feet.
• Use only your index finger to move the desk or table.

Constraints

• Can only use up to 100 pencils, tape and 25 rubber bands
• Use only the materials provided to you.

1. Break class into teams of 3-4.
2. Hand out the Getting your Bearings worksheet, as well as some sheets of paper for sketching designs.
3. Discuss the topics in the Background Concepts Section. Ask students to feel the strength of the friction when trying to move the lid (open part down) of the jar across different surfaces: desk top, tile floor, piece of carpet. Ask students to suggest different machines that incorporate ball bearings or roller bearings.
4. Review the Engineering Design Process, Design Challenge, Criteria, Constraints and Materials.
5. Provide each team with their materials.
6. Instruct students that they will be completing 3 activities and then a challenge.
   Activity 1: Students try moving the lid provided to them over several surfaces – book, desktop, floor, carpet.
   Activity 2: Students place just enough marbles in the jar lid to almost fill the space with marbles (they should not overfill it so that the marbles cannot move freely). Next, they should use a book to turn the lid over, and then try moving the lid with the marble “balls.”
   Activity 3: Students try a variation where a book or other weight is placed on top of the lid (with and without marbles).
7. Explain that for the challenge students must design a system using roller bearings to move one of the classroom desks, or a table, 10 feet. They should limit the force they apply to make the desk or table move to what they can push using only your index finger.
8. Announce the amount of time they have to design and build (1 hour recommended).
9. Use a timer or an on-line stopwatch (count down feature) to ensure you keep on time. (www.online-stopwatch.com/full-screen-stopwatch). Give students regular “time checks” so they stay on task. If they are struggling, ask questions that will lead them to a solution quicker.
10. Students meet and develop a plan for their roller bearing system. They agree on materials they will need, write/draw their plan, and present their plan to the class.
11. Teams build their designs.
12. Teams test their designs by showing how they can move the desk/table 10 feet with only their index finger.
13. As a class, discuss the student reflection questions.
14. For more content on the topic, see the “Digging Deeper” section.

Optional for Older Students

Work in teams to explore if other shapes of bearings might have advantages over the current ball or roller designs. Why or why not?

Student Reflection (engineering notebook)

1. Activity 1:
   – What was the difference in friction moving the lid across different surfaces?
   – Which surface exhibited the most friction? Why?
2. Activity 2:
   – What was the difference in the friction you experienced with the marbles rolling
   under the lid?
   – Did the marbles help on all surfaces? Only some?
   – Which surface, if any, now exhibited the most friction? Why?
3. Activity 3:
   – Does the marble base allow for easier movement when weights are added?
   – Can you think of an application for a device like this?
   – Who would need to move items with heavy weights? How would this help?
   – List three different machines that incorporate ball bearings or roller bearings.
4. Challenge:
   – Did you planned design work?  Why or why not?
   – What revisions did you have to make to your plan to make it a more effective solution?
   – Were you able to move the desk/table using only the force from one index finger?

The lesson can be done in as little as 1 class period for older students. However, to help students from feeling rushed and to ensure student success (especially for younger students), split the lesson into two periods giving students more time to brainstorm, test ideas and finalize their design. Conduct the testing and debrief in the next class period.

What is Friction?

How do Ball Bearings Help? 

Friction

Friction is a term that describes how much resistance there is for two objects to move over another. The greater the friction, the more difficult it is for the two objects to move smoothly. With less friction, objects move easily and smoothly against one another. For example, a piece of rubber would have greater friction moving over a carpet than a smooth textbook would. In machines, parts rub against each other and increased friction can wear out parts faster.

Ball Bearings

The term ball bearing sometimes means a bearing assembly which uses spherical bearings as the rolling elements. It also means an individual ball for a bearing assembly. Ball bearings are made of many different materials, including ceramics, metals, stainless steel, and other hybrid materials. They help reduce friction which keeps machines operating longer. They can also allow a machine to operate more quietly. Bearings were designed on a simple principle — that objects roll more easily than they slide. When two objects slide against each other, like a book on a table, or a jar on a carpet, the friction between the surfaces works to slow the motion. If the objects could instead, roll over each other, then the amount of surface area that touch is limited and so the friction is reduced.

Rolling Element Bearings

A rolling-element bearing is a bearing which carries a load by placing round elements between the two pieces. The relative motion of the pieces causes the round elements to roll (tumble) with little sliding. In the picture you can see how the balls are encased between the round parts. One of the earliest and best-known rolling-element bearings are sets of logs which are laid on the ground with a large stone block on top. As the stone is pulled, the logs roll along the ground with little sliding friction. As each log comes out the back, it is moved to the front where the block then rolls on to it. You can imitate such a bearing by placing several pens or pencils on a table and placing your hand on top of them.

Bicycles Without Ball Bearings? Roller Coasters Without Roller Bearings?

Bicycles are a great example of a machine that uses ball bearings to reduce friction. Ball bearings can be found in the pedals, in the front and rear hubs for the wheels, and the tube where the handlebars are attached. And skateboards and roller blades include ball bearings too! Beyond these examples, ball bearings are an important design element of oil drilling rigs, airplanes, and automobiles. Roller bearings are used in roller coasters!

Ball Bearing History – Product Evolution  

History

An early example of a wooden ball bearing supporting a rotating table was retrieved from the remains of a Roman ship in Lake Nemi, Italy. The wreck was dated to 40 BC. Leonardo da Vinci is said to have described a type of ball bearing around the year 1500. One of the issues with ball bearings is that they can rub against each other, causing additional friction, but this can be prevented by enclosing the balls in a cage. The captured, or caged, ball bearing was originally described by Galileo in the 1600s.

Innovation

Henry Timken, a 19th century visionary and innovator in carriage manufacturing, patented the tapered roller bearing in 1898. He envisioned a business built on solving a critical, age-old technical problem: friction, the force that impedes the motion of objects in contact with each other. “The man who could devise something that would reduce friction fundamentally,” Timken observed, “would achieve something of real value to the world.” The following year, he formed The Timken Company to produce his innovation.

Product Design and Improvement

Back when Henry began his development work, the dominant bearing was the plain, or “friction,” bearing which had been in use with little change since ancient times. It was essentially a metal liner in the hole around a rotating shaft, with the main work of friction reduction depending on lubrication. Henry began experimenting with ball bearings but they failed rapidly from wear. He concluded that “roller” bearings held greater promise for vehicles, such as automobiles, because the weight of the load –- so much heavier than on a bicycle –- could be carried along the full length of the rollers, as opposed to the single point of contact on each ball in ball bearings. Henry tried straight rollers but settled on tapered, which permitted bearings to sustain forces from all directions. Since 1899, The Timken Company has produced more than six billion bearings and now makes bearings of many different types.

Industries and Applications

Ball bearings are used in most industries, including transportation, aerospace, manufacturing, agriculture, and sports/entertainment. You’ll find some examples of ball or roller bearings used in aircraft landing wheels, wind turbines, satellites, and rolling mills. Miniature bearings can be found in medical applications such as dental equipment.

Internet Connections

• American Bearing Manufacturers Association – Bearing Timeline

Recommended Reading

• Timken: From Missouri to Mars – A Century of Leadership in Manufacturing (ISBN: 0875848877)
• Bicycling Science, by David Gordon Wilson (ISBN: 0262731541)
• Ball and Roller Bearings : Theory, Design and Application (ISBN: 0471984523)

Writing Activity

Write an essay or a paragraph describing three different machines that incorporate ball bearings or roller bearings. How does the use of the bearings improve the machine?

Alignment to Curriculum Frameworks

Note: Lesson plans in this series are aligned to one or more of the following sets of standards:

• S. Science Education Standards (http://www.nap.edu/catalog.php?record_id=4962)
• S. Next Generation Science Standards (http://www.nextgenscience.org/)
• International Technology Education Association’s Standards for Technological Literacy (http://www.iteea.org/TAA/PDFs/xstnd.pdf)
• S. National Council of Teachers of Mathematics’ Principles and Standards for School Mathematics (http://www.nctm.org/standards/content.aspx?id=16909)
• S. Common Core State Standards for Mathematics (http://www.corestandards.org/Math)
• Computer Science Teachers Association K-12 Computer Science Standards (http://csta.acm.org/Curriculum/sub/K12Standards.html)

National Science Education Standards Grades K-4 (ages 4-9)

CONTENT STANDARD B: Physical Science

As a result of their activities, all students should develop an understanding of

• Properties of objects and materials
• Position and motion of objects

CONTENT STANDARD E: Science and Technology

As a result of activities, all students should develop

• Abilities of technological design

CONTENT STANDARD G: History and Nature of Science

As a result of activities, all students should develop understanding of

• Science as a human endeavor

National Science Education Standards Grades 5-8 (ages 10-14)

CONTENT STANDARD B: Physical Science

As a result of their activities, all students should develop an understanding of

• Properties and changes of properties in matter
• Motions and forces
• Transfer of energy

CONTENT STANDARD E: Science and Technology

As a result of activities, all students should develop

• Abilities of technological design

CONTENT STANDARD G: History and Nature of Science

As a result of activities, all students should develop understanding of

• Science as a human endeavor
• History of science

National Science Education Standards Grades 9-12 (ages 14-18)

CONTENT STANDARD B: Physical Science

As a result of their activities, all students should develop understanding of

• Motions and forces
• Interactions of energy and matter

CONTENT STANDARD E: Science and Technology

As a result of activities, all students should develop

• Abilities of technological design
• Understandings about science and technology

National Science Education Standards Grades 9-12 (ages 14-18)

CONTENT STANDARD F: Science in Personal and Social Perspectives

As a result of activities, all students should develop understanding of

• Science and technology in local, national, and global challenges

CONTENT STANDARD G: History and Nature of Science

As a result of activities, all students should develop understanding of

• Historical perspectives

Next Generation Science Standards – Grades 2-5 (Ages 7-11)

Matter and its Interactions

• 2-PS1-2. Analyze data obtained from testing different materials to determine which materials have the properties that are best suited for an intended purpose.

Motion and Stability: Forces and Interactions

Students who demonstrate understanding can:

• 3-PS2-1. Plan and conduct an investigation to provide evidence of the effects of balanced and unbalanced forces on the motion of an object.

Engineering Design

Students who demonstrate understanding can:

• 3-5-ETS1-1.Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.
• 3-5-ETS1-2.Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.

Next Generation Science Standards – Grades 6-8 (Ages 11-14)

Engineering Design

Students who demonstrate understanding can:

• MS-ETS1-2 Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.

Standards for Technological Literacy – All Ages

Technology and Society

• Standard 6: Students will develop an understanding of the role of society in the development and use of technology.
• Standard 7: Students will develop an understanding of the influence of technology on history.

Design

• Standard 8: Students will develop an understanding of the attributes of design.

Standard 9: Students will develop an understanding of engineering

Step One:

Read the Student Reference Sheets to learn about bearings and the history and evolution of ball and roller bearings.

Step Two:

Working in groups of 3-4 students, try moving the lid provided to you over several surfaces – book, desktop, floor, carpet.

Question:

1. What was the difference in friction moving the lid across different surfaces? Which surface exhibited the most friction? Why?

Step Three:

Place just enough marbles in the jar lid to almost fill the space with marbles (do not over fill so marbles cannot move freely). Use a book to turn the lid over, and now try moving the lid with the marble “balls” providing assistance with friction lid moves across the same surfaces tried previously.

Questions:

1. What was the difference in the friction you experienced with the marbles rolling under the lid?

2. Did the marbles help on all surfaces? Only some? Which surface, if any, now exhibited the most friction? Why?

Step Four:

Try a variation where a book or other weight is placed on top of the lid (with and without marbles).

Questions:

1. Does the marble base allow for easier movement when weights are added?

2. Can you think of an application for a device like this? Who would need to move items with heavy weights? How would this help?

3. List three different machines that incorporate ball bearings or roller bearings.

1:_____________   2. ______________    3._____________

Optional Student Worksheet:
You are the Engineer!  Problem Solving with Roller Bearings

Instructions

You are the engineer!  Work in a team and devise a plan using roller bearings to move one of your classroom desks, or a table, 10 feet using materials provided.  Challenge:  limit the force you apply to make the desk or table move to what you can push using only your index finger.  You may use up to 100 pencils, tape.

Materials

One set of materials for each group of students:

• 100 Pencils
• tape
• rubber bands
• Section of carpet or rug

Step One:

Draw an illustration showing your planned solution below.

Step Two:

Try out your plan!  See if you can move the desk using only — engineers work in different scales all the time!

Questions:

1. Did you planned design work? Why or why not?

2. What revisions did you have to make to your plan to make it a more effective solution?

3. Were you able to move the desk/table using only the force from one index finger?