Featured in PASCO’s College Biology Instructor Guide

College Biology Instructor Guide


College Instructor edition with 26 experiments covering introductory and general biology topics.

Reflex vs Reaction

Lab Summary

Use a ruler, stopwatch, and reflex hammer to measure and compare human reflexes and reactions.


Students investigate somatic and autonomic reflexes in their own bodies and learn to distinguish reflexes from reactions. Students:

  • Distinguish between a reflex and a reaction.
  • Describe the differences between a stretch reflex and the pupillary reflex.


Students gain experience conducting the following procedures:

  • Measuring reaction rate using a meter ruler and stop watch.
  • Testing the patellar reflex using a reflex hammer.
  • Testing the pupillary reflex.

Materials Used:

Metric ruler 
Reflex hammer 
Stop Watch

The Associated Bundle:

College Biology Bundle


A complete probeware bundle designed for PASCO's College Biology curriculum

Interface Required

This experiment may require software and an interface for data collection.