**Friction**

Tobecksen, Alan Fenger H.S.

821-2830

**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.

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