The Nikolai Ski Challenge• Lesson Plan • 2012 IASD Thematic Unit

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The Science of Friction Lesson Plan Teacher: Denis Gardella Subject: Grade Levels: 3rd-9th Dates: 2-3 days _______________________________________________________________ Overview: Students will be dragging a block of wood across two (or it can be more) different grits of sandpaper with a spring scale and measuring the amount of force required to start the block moving and to keep it moving across the strip of paper. Activities: (Please click here to view ‘Friction’ lesson) Procedure

• If you’re using skis, you can put a portion of the ski bottom under the microscope and carefully take a picture of it by putting the camera lens right on the eyepiece of the microscope. This will be your “before” picture.

• Students will do the same with small samples of each grit of sand paper you use for this experiment.

• Students will then make a table in their lab report with each grit of sand paper as a header for each column of the table (see the Science of Friction below).

• They will pull the piece of 2x4 across one of the strips of sand paper with the spring scale and watch the scale carefully, recording the amount of force required to move the block across the strip.

• They will record this number in the appropriate column. They will do this at least 3 times, preferably more on each strip.

• They can average the readings together to get an average force required for that grit of sand paper.

• They will continue this process for each strip of sand paper used. • When the student is finished, he will have a number associated with each

grit of sand paper, the larger number (force) will be associated with the “grittier” sand paper.

• The numbers decrease as the sand paper gets finer. • Students will then wax their skis (instruction is ski resource section) and

take a picture of the ski under the microscope (the “after” picture) and make the association that waxing your skis reduces friction, thereby requiring less energy to move forward.

The Nikolai Ski Challenge• Lesson Plan • 2012 IASD Thematic Unit

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Curriculum Materials • A block of 2 x 4 four inches long with a hook in one end or a bent nail to

drag with the spring scale. • A spring scale that measures small forces and has hooks on both ends. 0

to 250 grams is a good choice. • Two (or more) 12-inch strips of widely variant grits of sandpaper, taped to

a table or other surface. • School camera; Microscope • Activity Page: Chart for recording readings

Assessment and Evaluation Students will make a small poster including the raw data of the experiment and pictures of each kind of sand paper correctly associated with the proper column in their table. They will include the before and after pictures of their skis (if you use skis). Students will write a conclusion defining what they discovered and associating their experimental findings with the practical reality of skiing and how much energy they will save by reducing friction. How is the quality of the poster? Are the photos of a good quality? Are the tables clear? Was their math accurate? Were their findings correct?

Sample of The Science of Friction poster by a middle school student.

A closeup of the report follows.

The Nikolai Ski Challenge• Lesson Plan • 2012 IASD Thematic Unit

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