Collapsing can or can crusher experiment is a demonstration of an

aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It ha ...

can being crushed by

atmospheric pressure Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, ...

. Due to the low

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...

inside a can as compared to the pressure outside, the pressure outside exerts a force on the can causing the can to collapse.

Explanation

The demonstration starts with boiling water inside the can. As the water is boiled,

water vapor (99.9839 °C) , - , Boiling point , , - , specific gas constant , 461.5 J/( kg·K) , - , Heat of vaporization , 2.27 MJ/kg , - , Heat capacity , 1.864 kJ/(kg·K) Water vapor, water vapour or aqueous vapor is the gaseous p ...

is created and filled the space inside the can which pushing air inside out. H₂O → H₂O Then, inverting a water vapor-filled can into a water bath causing water vapor to rapidly condense back to water. The condensation of water reduces pressure inside the can, so the higher pressure outside the can make the can collapse. H₂O → H₂O

Limitation

There will be an impeding event that could occur which is water in the water bath being drawn inside the can by the reduced pressure. As a result, in a basic demonstration, only an aluminum can is able to be used since it is not very strong. Unlike other stronger can such as steel can, the aluminum can will be collapsed before the water can be drawn inside the can. Nevertheless, Professor Julius Sumner Miller could make a

steel drum The steelpan (also known as a pan, steel drum, and sometimes, collectively with other musicians, as a steelband or steel orchestra) is a musical instrument originating in Trinidad and Tobago. Steelpan musicians are called pannists. Descript ...

collapse by sealing the opening of the drum after the water inside the drum boils and pouring water and ice onto the drum surface.

Alternatives

Addition of sodium hydroxide to a can filled with

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

can produce a similar result.Archived a
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Gallery

File:Can_crusher.webm, A video of collapsing can experiment File:Can_crusher_2.webm, A video of collapsing can experiment

References

{{commons category, Can crusher

External links

Can Crush Demonstration
Physics education Chemistry classroom experiments Articles containing video clips