# Helium answer from 2000 **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [April 21, 2008, 7:58pm UTC](https://boards.straightdope.com/t/helium-answer-from-2000/446292 "2008-04-21T19:58:51Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![tudza](https://avatars.discourse-cdn.com/v4/letter/t/cdc98d/32.png) [@tudza](https://boards.straightdope.com/u/tudza)\ **Post date:** [April 21, 2008, 7:58pm UTC](https://boards.straightdope.com/t/helium-answer-from-2000/446292/1 "2008-04-21T19:58:51Z")
The answer seems reasonably complete, but you may want to add an explanation concerning the speed of sound in various mediums. People remember from science class that sound travels more quickly in _more dense_ materials, thinking of examples given using solids. The article states that helium is _less dense_ and so sound moves more quickly. The whole business of speed of sound in various materials is a little more complex than just density it seems, looking over the various equations on wikipedia. Check out the recent back and forth on Wired: > **[Three Smart Things You Should Know About Helium](https://www.wired.com/2008/03/st-3smart-8/)** > > 1 Although helium is the second-most-plentiful element in the cosmos — it's synthesized in stars by nuclear fusion — Earth is running short of the noble gas. Extracted from natural gas, our supply accumulated in the planet's crust over billions of... ---
**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\ **Post date:** [April 22, 2008, 11:45am UTC](https://boards.straightdope.com/t/helium-answer-from-2000/446292/2 "2008-04-22T11:45:28Z")
The column in question is [Why does helium make your voice squeaky?](http://www.straightdope.com/mailbag/mheliumsqueak.html) (14-Jul-2000). Just to clarify, sound travel faster in \*stiffer \* materials, and slower in \*denser \* materials. Whether or not people in general \*think \* that sound travels more quickly in denser materials I do not know. I imagine some people do, but “some” people will believe anything. ---
**Author:** ![tudza](https://avatars.discourse-cdn.com/v4/letter/t/cdc98d/32.png) [@tudza](https://boards.straightdope.com/u/tudza)\ **Post date:** [April 22, 2008, 8:19pm UTC](https://boards.straightdope.com/t/helium-answer-from-2000/446292/3 "2008-04-22T20:19:33Z")
Sure, some people will believe anything, but I’m not talking about faith healing or UFO research or cryptozoology. I’m talking about mistaken belief based on past science instruction. You will note in that Wired article comment section someone says “You are wrong in your explanation because I was taught that denser materials transmit sound faster.” This caused to to examine several sources to arrive at a better understanding. Wikipedia states the case like this: > **[Speed of sound](https://en.wikipedia.org/wiki/Speed_of_sound#Basic_concept)** > > The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. At 20 °C (68 °F), the speed of sound in air is about 343 metres per second (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn), or one kilometre in 2.91 s or one mile in 4.69 s. It depends strongly on temperature as well as the medium through which a sound wave is propagating. At 0 °C (32 °F), the speed of sound in air is about 331 m/s (1,086 ft/s; 1,192 km/h; 740 mph; 643 kn). More It’s that last paragraph I’m talking about. What I am saying is that I saw an example of what I believe will be a common objection to your explanation. If anyone believes it is important enough, I suggest adding more information to that explanation. ---
**Author:** ![C\_K\_Dexter\_Haven](https://avatars.discourse-cdn.com/v4/letter/c/b2d939/32.png) [@C\_K\_Dexter\_Haven](https://boards.straightdope.com/u/C_K_Dexter_Haven)\ **Post date:** [April 23, 2008, 7:52pm UTC](https://boards.straightdope.com/t/helium-answer-from-2000/446292/4 "2008-04-23T19:52:27Z")
An interesting thought. The problem is that **Alphagene** no longer writes Staff Reports, and the energy and effort involved in revising an eight-year-old report is more than it’s worth. If we have a volunteer to write an addendum, I’ll be glad to consider it.