Friction

Tobecksen, Alan                   Fenger H.S.
15310 Harper                      821-2830
Dolton, Il                       
849-1708                     

Objectives:

1. Students will observe that friction is a force opposing movement.
2. Students will observe that different surfaces have different 
   coefficients of friction.
3. Students will observe that friction is more dependent on mass 
   rather than surface area.
4. Students will observe that there is a difference between static 
   (starting) and sliding friction.
5. Students will perform experiments and record measurements and make 
   data tables.
6. Students will observe that there are differences in the 
   measurements and will postulate as to why.

Apparatus Needed:

heavy books, aluminum foil, wax paper, plastic bags, sandpaper, ditto 
paper, string, tape, spring balances.

Recommended Strategy:

Present the problem to the students - which wrapped book will be the 
hardest to pull, which will be the easiest to pull.  Have the students, 
as a group, order the wraps from hardest to easiest (a typical answer - 
sandpaper, aluminum foil, ditto paper, plastic, wax paper.)  Let the 
students touch the wrappings to get the "feel" of them.  Students will 
then experiment with the equipment to find the right order of 
wrappings, the difference between static (starting) friction and 
sliding friction, and whether there is a difference when the book is 
turned on edge versus flat on the table.