M5 Plastic Bottle Cannons

Background

Elements in the periodic table can be classified in a number of ways. One of those ways is based on their physical states. While there are numerous solids, there are only some gases and just a few liquids. Regardless, all of them can be further classified and distinguished by their appearance. Apart from that, they can also be distinguished by some very basic chemical reactivity to some standard reagents, such as air, water and acid.

Additionally, the vigor of the reaction between an element and a reagent provides clues about the relative quantities of the chemicals reacted.

Resources:

  1. M4 Periodic Table I: Periodic Table: All about the periodic table and it’s elements.
  2. M5 Stoichiometry III: Chemical Reaction & Reaction Stoichiometry: Descriptions of what chemical equations and reactions are and the information furnished by them!
  3. M5 Stoichiometry IV: Mass Relationships: Descriptions of how chemicals in a reaction are related to one another quantitatively.
  4. M4 Fuels and Energy: This page contains links to two PowerPoint slides: one on Energy Changes and the other on Fuels and Energy.

Discrepant Event

The video below appeared as stimulation for the MYP4 task with the same name.  This exercise however contains more questions.

The video demonstrates an explosive reaction between two gaseous elements. Mixtures of the two gases are contained in three different plastic bottles with a rubber bung at the mouth. The reaction is initiated by introducing a lit match next to a small hole on the side of the bottle covered with a small cello (scotch) tape.

Though all three contain mixtures of the same two gases, the reaction is a little different from one another in its vigor/explosiveness. Watch the video to see and hear the results.

Here are the question:

  1. If you did not attempt the M4 version of this task, first identify gases in the plastic bottle. The gases are colorless and odorless.  (All you are being asked to do is use your knowledge of the periodic table and some basic properties about the elements on it.)
  2. List some observations about the canons which show that the energy involved, the explosiveness of the reactions, were different. (The final canon was shot outside as the loudness would have been a little too much in the laboratory. All three bottle were of the same capacity.)
  3. Explain the difference in the loudness.
  4. Physics extension: Design an investigation to determine the energy output by the explosion.

Concept involved:

  • periodic table, reactive gases, physical properties, color, odor.
  • stoichiometry, stoichiometric ratio, mole ratio, volumetric ratio,

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