Lesson 3 – Inferences from Proxy Variables-Mock AFM

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Course:  Integrated Science, Physics, Biotechnology and/or STEM courses

Unit:  Measurement, Scientific Process, and Instrumentation Design


See Standards Addressed for all NGSS, WA State (Science, Math and Literacy), and NOAA Ocean Literacy Education Standards Connections.  In addition to the aligned objectives linked above, for this lesson, here is a breakdown of:

What Students Learn:

  • Observation is the skill of recognizing and noting some fact or occurrence in the natural world. Observation includes the act of measuring.
  • To infer is to arrive at a decision or logical conclusion by reasoning from evidence.
  • Scientists use observations to make inferences.
  • Additional information can improve the validity of inferences.
  • Proxy variables can be used to make observations.
  • An Atomic Force Microscope (AFM) uses repulsive force as a proxy variable to make observations of surfaces at the atomic scale. Processing the data with of visualization software, scientists infer surface structure from these observations.
  • Increased resolution can provide additional information.
  • Design solutions involve tradeoffs.

What Students Do:

  • Make observations and generate inferences about differing types of data.
  • Use “touch” data to draw an unknown object in a bag.
  • Make inferences about the identify of the object from the drawings.
  • Use a mock Atomic Force Microscope (AFM) to infer surface structure from “touch” data processed with Excel into a 3D graph.
  • Brainstorm ways to improve the design of their mock AFM & evaluate the trade-offs.
  • Evaluate the limitations of utilizing proxy variables to take measurements.
  • Evaluate the limitations of observation to infer patterns or make predictions.

 *Access a short article on new techniques to measure brain activity.  This article specifically discusses brain neurology as a system and the need for novel ways to “see” into it.  Taken from the August 2011 HHMI Bulletin, vol. 24, No. 3.  “Let’s Get Small” by Helen Fields.