Gases- Collapsing Can

Collapsing  Can

Description: A 5-gallon metal can is collapsed under external air pressure either by evacuating the can, or boiling water in it, sealing the can and allowing it to cool.

Description II: Water is boiled in a square can. The can is quickly inverted into a container of water, and the can spontaneously crushes. This demo can also be performed using a vacuum pump to remove air from the can, until atmospheric pressure is sufficient to collapse it.

This demonstration is also available on video and JCE “Chemistry Comes Alive!”  Vol. 1 CD-Rom.

Source: Shakhashiri, BZ  Chemical Demonstrations: A Handbook for Teachers of Chemistry

Year: 1985  Vol: 2  Page: 6

Keywords:  Water, Vacuum, Square can, Pressure, Collapse, Force

Rating:

Hazard: Some

  • Electric shock hazard
  • Slip hazard
  • Flammability hazard
  • Burn hazard

Effectiveness: Good

  • Clearly observable without guidance
  • Good connection from demo to course material
  • Low failure rate
  • Time to results is low
  • Clear contrast between behavior of systems

Difficulty: Medium

  • Simple manipulations for most to perform
  • Some intermediate steps to results
  • Simple procedures
  • Demos at non-standard conditions

Safety Precautions:

  • Gloves recommended
  • Eye protection required
  • Absorbent material on hand
  • Flame resistant surface recommended
  • Use of UL approved three-prong plug and outlet

Class: Gas Law, Intermolecular Forces

Division: General, Physical Chemistry