Coffee Shop: Caffeine Experiment

By Laura Hospitál on Jun 30, 2016

This science project was done by Dottie, who is a student at Texas School for the Blind and Visually Impaired (TSBVI).


Which one affects your heart rate the most: decaf or caffeinated coffee?

After doing research with a volunteer on how caffeine affect the heart,  Dottie's hypothesis was:


The caffeinated coffee will increase heart rate more than decaf coffee. 


  • This experiment required setting up the cups, sugar, and creamer for each trial.
  • Dottie also prepared the talking heart rate monitor for use.


  • 15 coffee cups
  • Instant decaf coffee
  • Instant caffeinated coffee – Same brand
  • Sugar in packets
  • Coffee creamer
  • Stop Watch
  • Talking heart rate monitor
  • Napkins
  • Talking calculator


  1. Volunteer will sit on chair
  2. After 5 minutes, take resting heart rate using the talking heart rate monitor and record heart rate in the table
  3. Volunteer will be given a cup prefilled with 6 oz. of decaf coffee
  4. Wait 15 minutes.
  5. Take heart rate again and record the data in the data table.
  6. Give volunteer a cup of caffeinated coffee.
  7. Wait 15 minutes.
  8. Take heart rate and record the data in the data table
  9. Compare heart rate before and after decaf and caffeinated coffee and analyze the data
  10. Draw a conclusion. 


Average change of heart rate:

  • Caffeinated coffee:         8.29 bpm
  • Decaffeniated coffee:     3.00 bpm


The hypothesis was correct, the caffeinated coffee raised heart rate more


Dottie and the volunteer who worked with her discussed the possibilty of comparing the effect of caffeinated and decaf coffee on females versus males.

NGSS Standards:

Plan and conduct an investigation individually and collaboratively to produce data to serve as the basis for evidence, and in the design: decide on types, how much, and accuracy of data needed to produce reliable measurements and consider limitations on the precision of the data (e.g. number of trials, cost, risk, time), and refine the design accordingly. (HS-ESS2-5)

Caffeine collage
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