Discovering Friction

http://www.teachengineering.org/view_lesson.php?url=collection/duk_/lessons/duk_friction_smary_less/duk_friction_smary_less.xmllessontext/xmlDiscovering FrictionEngineering K-Ph.D. Program, frictionstatic frictionkinetic frictionfrictionstatic frictionkinetic friction

With a simple demonstration activity, students are introduced to the concept of friction as a force that impedes motion when two surfaces are in contact. Then, in the Associated Activity (Sliding and Stuttering), they work in teams to use a spring scale to drag an object such as a ceramic coffee cup along a table top or the floor. The spring scale allows them to measure the frictional force that exists between the moving cup and the surface it slides on. By modifying the bottom surface of the cup, students can find out what kinds of surfaces generate more or less friction. They also discover that both static and kinetic friction are involved when an object initially at rest is caused to slide across a surface.

Engineers must understand how friction affects a number of situations, from the bottom of skis in which friction is a disadvantage to hiking boots where friction provides traction. students will be able to describe friction as a force that impedes motion and generates heatstudents will be able to distinguish between static friction and kinetic frictionstudents will be able to explain why friction occursstudents will be able to describe common occurrences of friction, including those in which friction can be used to advantage in everyday lifestudents will be able to describe ways in which friction can be reduced 2TeachEngineering.orgMary R. Hebrank (Project Writer and Consultant), Pratt School of Engineering, Duke UniversityS101DA63North_CarolinaMath2.01 Estimate and measure length, perimeter, area, angles, weight, and mass of two- and three-dimensional figures, using appropriate tools.66S1028413North_CarolinaScience1.01 Identify and create questions and hypotheses that can be answered through scientific investigations.66S102841ENorth_CarolinaScience1.05 Analyze evidence to: • Explain observations.66S1028421North_CarolinaScience1.06 Use mathematics to gather, organize, and present quantitative data resulting from scientific investigations: • Measurement.66S1028428North_CarolinaScience1.08 Use oral and written language to: • Defend conclusions of scientific investigations.66S10284AFNorth_CarolinaScience1.01 Identify and create questions and hypotheses that can be answered through scientific investigations.77S10284BANorth_CarolinaScience1.05 Analyze evidence to: • Explain observations.77S10284BDNorth_CarolinaScience1.06 Use mathematics to gather, organize, and present quantitative data resulting from scientific investigations: • Measurement.77S10284C4North_CarolinaScience1.08 Use oral and written language to: • Defend conclusions of scientific investigations.77S1028520North_CarolinaScience6.03 Evaluate motion in terms of Newton's Laws: The force of friction retards motion. 77S1028527North_CarolinaScience6.05 Describe and measure quantities that characterize moving objects and their interactions within a system: • Time.77S1028531North_CarolinaScience1.01 Identify and create questions and hypotheses that can be answered through scientific investigations.88S102853CNorth_CarolinaScience1.05 Analyze evidence to: • Explain observations.88S102853FNorth_CarolinaScience1.06 Use mathematics to gather, organize, and present quantitative data resulting from scientific investigations: • Measurement.88S1028546North_CarolinaScience1.08 Use oral and written language to: • Communicate findings.88United StatesCopyright 2012 - Engineering K-Ph.D. Program, Pratt School of Engineering, Duke Universityhttp://www.teachengineering.org/policy_ipp.phphttp://www.teachengineering.org/2008-09-267Teacher