The use of systems in many introductory courses is limited and often implicit. Modeling two or more objects as a system and tracking the center of mass of that system is usually not included. Thinking in terms of the center of mass facilitates problem solving while exposing the importance of using conservation laws. We present below three laboratory activities that build this systems thinking for introductory physics students.

1.
One of the Five Big Ideas of the AP Physics 1 Curriculum
is “
interactions between systems can result in changes in those systems
.” (
AP Physics 1: Algebra-Based and AP Physics 2: Algebra-Based Course and Exam Description Including the Curriculum Framework Effective Fall 2014
, accessed Aug. 3, 2016, from http://media.collegeboard.com/digitalServices/pdf/ap/ap-physics-1-2-course-and-exam-description.pdf.
3.
Lou
Turner
, “
System schemas
,”
Phys. Teach.
41
,
404
408
(
Oct.
2003
).
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