Speed of Sound in Materials: Impact on "Vaporization" Gun

  • Context: Undergrad 
  • Thread starter Thread starter Jota
  • Start date Start date
  • Tags Tags
    Gun Vaporization
Click For Summary
SUMMARY

The discussion focuses on the speed of sound in various materials and its implications for a "vaporization" gun concept. Key materials and their sound speeds include Diamond at 12,000 m/s, Pyrex glass at 5,640 m/s, and Iron at 5,130 m/s. The conversation explores whether vaporizing a material in a gun's firing chamber could propel a projectile at the speed of sound through that material. It concludes that while the speed of sound dictates the maximum speed of an impulse through a solid, the actual propulsion would depend on factors like heat conduction and material properties.

PREREQUISITES
  • Understanding of speed of sound in materials
  • Knowledge of thermodynamics related to vaporization
  • Familiarity with projectile propulsion mechanisms
  • Basic principles of material science, particularly molecular mass and heat capacity
NEXT STEPS
  • Research the properties of materials with low molecular mass for gas generation
  • Explore the mechanics of shock wave propagation in solids
  • Investigate existing high-speed air gun technologies used in ballistics research
  • Learn about the thermal dynamics of rapid heating and vaporization processes
USEFUL FOR

Engineers, physicists, and researchers interested in advanced propulsion systems, material science, and thermodynamics related to vaporization and shock wave dynamics.

Jota
Messages
17
Reaction score
0
"vaporization" gun

I got my information on speeds of sound through various materials from this page: http://hyperphysics.phy-astr.gsu.edu/hbase/tables/soundv.html#c1

Material v (m/s)
Diamond 12000
Pyrex glass 5640
Iron 5130
Aluminum 5100
Brass 4700
Copper 3560
Gold 3240
Lucite 2680
Lead 1322
Rubber 1600



This might sound a little crazy, but I'm a kind of 'curiousity-addict', so I'll ask anyway: If one of these substances were placed in the firing chamber of some kind of gun, a projectile placed in front of it, and then said substance was vaporized, would it expand at the same speed as sound travels through them, and therefore propel the projectile at that speed? Assuming of course both gun and projectile were made of an exotic material strong enough to withstand the friction.
 
Physics news on Phys.org
Not necessarily.
The speed of sound is the fastest an impulse can travel through a material, so if you were trying to vaporise it by hitting one end very hard then the shock wave would travel at the speed of sound through the unmelted part.

You could apply enough heat around the entire projectile to vapourise it quickly and then let the expanding gases propel the projectile.
This wouldn't depend on the speed of sound but would be limited by the poor conduction from the evaporating part to the still solid centre.
You should probably look for a material with low molecular mass (so you get as many moles of gas as possible) low melting point and low specific heat capcaity.
A similair system is already used to make very high speed air guns for ballistics research. A block of plastic is heated very quickly by powerful x-rays to generate gas which fires a projectile.
I'm not sure why this is used rather than explosives, it might be that the vaporisation of the plastic is faster than typical explosive velocities or it might be to keep a chemically pure atmosphere without the combustion products of an explosive.
 

Similar threads

Mathematica This Week's Finds in Mathematical Physics (Week 231)
  • · Replies 5 ·
Replies
5
Views
3K
Mathematica This Week's Finds in Mathematical Physics (Week 231)
  • · Replies 5 ·
Replies
5
Views
3K