Objective:  Students will discover how friction affects a moving object.

Materials:  a smooth surface (floor or table), 3 small wooden blocks(or per group) sandpaper, petroleum jelly, Science Journal

Vocabulary:  friction

Duration:  1-2 days, 30-40 minutes

Grouping:  Coop groups or whole class

Preparation:  Glue a piece of sandpaper to one block (or one block per group).  Coat the bottom of one block (or one block per group) with petroleum jelly.

Activate prior knowledge:  Ask one or two students to explain homework pictures (lesson 2).  Ask students how work can be reduced.

Activity:  (1) Ask students what will happen when they slide each block across the floor or table (Be sure they apply the same amount of force each time.). (hypothesis)
(2) Slide each block across the table or floor.  Measure the distance traveled.  Record data on chart or in journal.
(3) Conclusion-(Example) The block coated with petroleum jelly slid the farthest because the petroleum jelly decreased the friction between the blocks.