Friction Lab: Drags, Surfaces and Stops

Students take simple measurements of friction by dragging a mat with a classmate on it across different surfaces, using how far a resistance band stretches as a homemade force gauge. Then they apply it to stopping and cutting while running and discuss how shoes and surfaces affect injury prevention.

How to play

1. Explain that friction depends on weight and surface type, and show the homemade force gauge: a band tied to the mat and a tape measure to see how far it stretches (4 min).
2. In groups of four, drag the mat at a steady speed with a classmate sitting on it across three surfaces: concrete court, grass or dirt, and gym floor; record the stretch (9 min).
3. Change the load: drag the empty mat and then with two classmates on it, and check whether the stretch grows in proportion (5 min).
4. Stops: run 10 m and stop sharply inside a cone zone on two surfaces; the group measures the stopping distance (7 min).
5. Conclusions: link the data to shoes, wet floors and slips, and come up with three prevention tips (5 min).

Rules

• Whoever rides the mat stays seated, holding the handles, and never stands up.
• Drags are done walking, never running.
• Stops are done only in athletic shoes and on dry surfaces.
• Tie the band with a double knot and nobody stands in its line of pull.

Variations

Adaptations

• Limited mobility: measure the band stretch and test stopping by pushing the wheelchair on two surfaces.
• Visual impairment: a partner guides the student during the drag and the stopping zone is marked with raised tape.
• Ankle injury: skip the stops and keep the group's distance log.

Learning goals

• Test how mass and surface affect the force of friction.
• Relate friction to stopping and cutting technique.
• Suggest ways to prevent slips and injuries based on shoes and surfaces.

Equipment for a class of 25

• mats: 7
• resistance bands: 7
• tape measure: 7
• cones: 14
• worksheets: 7

Teacher tip

Calibrate one band ahead of time by hanging 10 and 20 lb sandbags so the data make sense. Skip the stops if the floor is damp.

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