Getting Your Bearings

Student Worksheet:

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

4. 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:
5. Does the marble base allow for easier movement when weights are added?  

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

7. List three different machines that incorporate ball bearings or roller bearings.
	1:_____________   2. ______________    3._____________

      Getting Your Bearings

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: 
o	100 Pencils
o	tape
o	rubber bands
o	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?