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Experiment #2 from Investigating Motion

Education Level
Elementary School


Have you ever wondered how automatic doors at grocery stores know when to open? There is a sensor over the door that detects objects, such as a person walking up to the door.

The Motion Detector that you will use in this activity can also do this. The Motion Detector works by sending out a signal and then measuring how long it takes for reflections to return to the sensor. Based on the amount of time it takes the signal to bounce back, the data-collection software is able to calculate the position of the object.


  • Explore the different lines and curves produced by moving in front of the Motion Detector.
  • Learn to write detailed steps for creating an M or W shape on the graph.
  • Match different letter and designs drawn on the graph.

Sensors and Equipment

This experiment features the following sensors and equipment. Additional equipment may be required.

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This experiment is #2 of Investigating Motion. The experiment in the book includes student instructions as well as instructor information for set up, helpful hints, and sample graphs and data.

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