1N22.35 Alcohol Rocket

Concepts

Conservation of momentum

Overview

This bottle rocket runs on ethanol, ejecting the hot products of ethanol combustion. It is fairly loud and moves very quickly. This will get everyone's attention.

Details

Equipment

  • [2] 2-L bottle with hole in the cap
  • [1] Lab stand
  • [1] Rotatable clamp
  • [1] Launcher platform
  • [2] C-clamp
  • [1] BBQ lighter or box of matches and match-holder
  • [1] Bottle of ethanol
  • [1] Fire extinguisher

Classroom Assembly

  1. Clamp the launcher platform to the lab stand.
  2. Clamp the lab stand to a table.
  3. Adjust the launcher platform so that a launched bottle will not hit anyone or light anything (or anyone) on fire.

Important Notes

  • Make sure the launcher platform is high enough and angled so that flames from the bottle do not set anything on fire, especially the matches or lighter, the bottle of ethanol, and yourself
  • Aim the bottle rocket well away from people! It moves very quickly and its trajectory can vary. 

Script

  1. Spray the inside of the 2-L bottle with ethanol, adding enough to coat the inside walls.
  2. Rotate the bottle ensuring a good coating on the inner wall.
  3. Mount the bottle on the launcher.
  4. Activate the BBQ lighter or ignite a match and put it on the match-holder.
  5. Ignite the rocket, keeping your hands far from the bottle.

 

Additional Resources

References

  • PIRA 1N22.35

Disclaimer

  • Don't attempt this at home!

Last revised

  • 2020

Technicals

  • If re-using rockets immediately after a launch, re-oxygenate the bottles by squeezing and expanding the bottles a few times.
  • The propulsion effect is due to both heating of the gas in the bottle and due to production of more gas molecules. The chemical reaction is as follows:
    C2H6O + 2 O2 → 3 H2O + 2 CO2

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If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.