Wikipedia:Reference desk/Archives/Science/2013 May 21

= May 21 =

what is the most amazing tornado footage ever filmed?
I would like to see some clear, compelling footage of a tornado destroying human habitats. Not a Hollywood movie, but real footage. I could just type tornado footage into Youtube and go fishing, but can you recommend a specific video?--Jerk of Thrones (talk) 04:34, 21 May 2013 (UTC)


 * Counter-intuitively, a smaller tornado may provide more graphic destruction. The larger ones tend to have a large dust cloud around them, obscuring the action, and the scale also makes it hard to pick out details.  (What appear to be dots on the screen might be cars thrown about, for example.)  Also, huge tornadoes don't twist much, and that makes them less interesting.


 * Double or triple tornadoes, where they twist around one another, are also visually interesting. StuRat (talk) 06:41, 21 May 2013 (UTC)


 * Start at National Severe Storm Laboratory's tornado education website, maintained by NOAA. They link to several videos.  Nimur (talk) 11:54, 21 May 2013 (UTC)


 * Or watch CNN late afternoon US central time this week and keep your DVD recorder on standby. Count Iblis (talk) 13:02, 21 May 2013 (UTC)


 * Or watch this. Count Iblis (talk) 13:25, 21 May 2013 (UTC)

You might consider also waterspouts and fire devils. μηδείς (talk) 00:19, 22 May 2013 (UTC)

Spoiled Tabasco
Will my tabasco sauce spoil if I don't use it fast enough. Will mold and bacteria infest my precious tabasco sauce? — Preceding unsigned comment added by 128.214.48.186 (talk) 09:56, 21 May 2013 (UTC)


 * Unless you let some foreign matter into the bottle, vinegar and salt is a very unwelcoming place for anything to grow. An FAQ at tabasco.com gives a shelf life of five years for the regular variety, after which harmless discoloration may occur, but it shouldn't really spoil. You may want to shake an old bottle in case the ingredients have separated. Spices tend to lose their potency over time, so a really old bottle may taste different. 88.112.41.6 (talk) 11:17, 21 May 2013 (UTC)


 * To make it last longer:


 * 1) Refrigerate it (even if the label doesn't say you need to, this will still extend it's life).


 * 2) Keep bacteria out by keeping the lid on. When you use it, the lid should be off for seconds, not minutes or hours.  And definitely don't pour it into a bowl, use the bowl for dipping, then pour it back into the bottle. StuRat (talk) 14:40, 21 May 2013 (UTC)


 * This is purely anecdotal, but I once found an old bottle of tabasco (in my grandparents' larder) on which the lid had split and no longer sealed, most probably some considerable time before. The sauce had lost its red colour (it was a sort of pale green - and no, it wasn't the green tabasco), most of its flavour and all of its heat. The advice about keeping the lid on is good, as is the advice about not pouring it back into the bottle, although the size of the opening on most sizes of tabasco bottle make that nigh on impossible anyway. Equisetum (talk &#124; contributions) 15:02, 21 May 2013 (UTC)


 * Yes, it would involve use of a funnel. StuRat (talk) 21:59, 21 May 2013 (UTC)


 * I am no expert, please do not try this, it may be unhealthy or risky! I once opened a bottle that I didn't finish for probably more than a year (could even have been 2-3 years). Having grown up in Africa I believe one does not waste food (unless I'm fairly certain it will be bad for me). I kept the cap on in a cupboard. It turned brownish, but that Tabasco Sauce tasted better to me than the fresh kind (I also use it in restaurants and other places). Not sure how it works, probably some ageing that occurs that subjectively can enhance the flavor. Or possibly the flavor was more noticable because it had less heat. I didn't notice any undesirable effects from using it. 105.236.19.62 (talk) 12:35, 25 May 2013 (UTC) Eon


 * One of the main benefits of spices is that they are preservatives, which rubs off on spicy condiments. μηδείς (talk) 00:16, 22 May 2013 (UTC)


 * Just to verify specifically what Medeis has alluded to, Capsicum varieties have been shown to have mildly anti-microbial properties, see this paper for example, mostly due to the capsaicin itself. So, even beyond the salt and vinegar, the Tabasco peppers themselves should be somewhat preservative.  Which doesn't mean that peppers never rot, but that they do have compounds within them that inhibit bacterial growth.  -- Jayron  32  03:19, 22 May 2013 (UTC)
 * The vinegar and salt would be the strongest of the three preservatives here. But I have never seen jarred hot peppers go bad.  Oil also works as a preservative, since most bacteria require a more aqueous environment to thrive.  Indeed, I have never had even half and half go bad on me due to the fat content. μηδείς (talk) 04:44, 22 May 2013 (UTC)

OK, we seem to be adequately answered, time for a distraction: --184.100.92.44 (talk) 01:19, 22 May 2013 (UTC)
 * Q: How can you tell that an Iowa couple has been married for a REALLY long time?
 * A: They're on their second bottle of Tabasco!

why atomic silver clusters catalyze ionic silver reduction?
It's about photographic film development. General background like, silver halide is photosensitive and when it's hit by photon, few but electroconductive silver atoms formed on the silver halide crystals, then silver atom bearing sites become very sensitive to reducing agent and get reduced faster. Now the question, what is behind this atomic silver catalyzator? Why it catalyzes the redox reaction? I don't understand why atomic silver turns to be a catalyzator for silver ions. — Preceding unsigned comment added by 134.130.94.148 (talk) 13:53, 21 May 2013 (UTC)
 * This article seems to be a good introduction to the process. -- Jayron  32  14:52, 21 May 2013 (UTC)

Deriving the Saha equation Using statistical Mechanics
For a system consisting of hydrogen atoms and hydrogen ions, (i.e. where each particle is in one of two possible states: unoccupied (no electron present) and occupied (one electron present, in the ground state)), the Saha equation says that $$\frac{P_p}{P_H}= \frac{kTn_Q}{P_e}e^{-I/kT}$$

where $$P_p$$ is the partial pressure of the ionized hydrogens, $$P_H$$ is the partial pressure of un-ionized hydrogens, and $$P_e$$ is the electrons pressure. $$I$$ is the ionization energy.

Is it possible to derive this equation, using statistical mechanics? AnalysisAlgebra (talk) 15:35, 21 May 2013 (UTC)

Yes, you can start with deriving the fact that in an equilibrium reaction where particles A1, A2, A3react and you get particles B1, B2, B3, according to the reaction formula

a1 A1 + a2 A2 + a3 A3.... <---> b1 B1 + b2 B2 + b3 B3 + ....

the chemical potentials of the particles A1, A2, A3,...B1, B2, B3 satisfy the equation:

a1 muA1 + a2 muA2 + a3 muA3 +.... = b1 muB1 + b2 muB2 + b3 muB3 + ....

Then, assuming that the particles are weakly interacting and that you therefore have an ideal gas, the chemical potential can be expressed in terms of the one particle partition function. The above formula for the chemical potential then implies:

(Na1/Za1)^a1 (Na2/Za2)^a2 (Na3/Za3)^a3...= (Nb1/Zb1)^b1 (Nb2/Zb2)^b2 (Nb3/Zb3)^b3...

where Zar and Zbr are the single particle partition function for particles of type ar and br. Count Iblis (talk) 16:01, 21 May 2013 (UTC)
 * Are you trying to say $$Z_{H} = Z_pZ_e$$?? But what are these quantities? What is the energy of an isolated electron? AnalysisAlgebra (talk) 16:53, 21 May 2013 (UTC)
 * I forgot to inser the particle numbers in the formula, the correct expression is

$$\frac{N_{H}}{Z_{H}} = \frac{N_p}{Z_p}\frac{N_e}{Z_e}$$. The partition functions are quite easy to calculate, you only have to take into account the binding energy in Z_H. If we forget about the binding energy, we have for a particle of mass m that $$Z=V\left(\frac{2\pi m k T}{h^2}\right)^{\frac{3}{2}}$$. Here V is the volume. Now you have to multiply this by the spin degenracy, whch for hydrogen is 4 and for the proton and electron is 2,. but then these factors cancel out in the above equation. Then, Z_H gets an extra factor of exp[-Eb/(k T)] where Eb = -13.6 eV is the binding energy.
 * So, to summarize, what you have to do is to use the fact that in an isolated system the entropy is maximla in thermal equilibrium to prove the relation between the chemical potentials. Then you can do the same for a system kept at constant temperature and volume (there the Helmholtz free eenrgy is minimal, which you have to be able to prove also), or for a system kept at constant pressure and volume where the Gibbs free energy is minimal. In all these cases you get the same relation between the chemical potentials.
 * Next, you derrive the equation for the chemical potential e.g. by usung the fact that the Helholtz free energy is F = -k T Log(Z) where now Z is the full partition function of the system  and that dF = -S dT - P dV + mu dN, so the partial derivative of F w.r.t. N at constant T and V is equal to mu. Then the partition function for an ideal dilute gas consisting of Nj molecules of type j is given by Z = Z1^N1/N1! Z2^N2/N2! ...., where the Zj are the single particle partition functions. You can to derive this by using the definition fo the partition function and the fact that permuting the dientical particles doesn't yield a new state. Then if the gas is dilute you only have a negligible contribution to the partition function where more than one particle of the same type are in the same state. This allows you to compute the partition function by taking the products of the powers of the one particle partition function and then divide by the factorials of the particle numbers to compensate for the overcounting. Count Iblis (talk) 18:08, 21 May 2013 (UTC)
 * So $$ \frac{N_H}{m_H^{3/2}e^{I/kT}} = \frac{N_p}{m_p^{3/2}}\frac{N_e}{V\left(\frac{2\pi m_e k T}{h^2}\right)^{3/2}}$$. But that doesn't imply the statement I want to prove, does it?? For example, there's no extra factor of $$kT$$. AnalysisAlgebra (talk) 03:03, 22 May 2013 (UTC)


 * What you get using the ideal gas law and approximating the ratio of the proton and hydrogen mass as 1 is


 * $$\frac{P_e P_p}{P_H}= k T \exp\left(-\frac{I}{k T}\right)\frac{Z_e}{V}$$


 * Ze/V is also sometimes denoted as nQ. You can interpret the single particle partition function per volume as the effective number of quantum states available per particle per unit volume, so, it's a density of quantum states for the electron hence the symbol nQ. To see this, consider that the partition function for a single particle is just the sum over exp[-E/(kT)] over all the available quantum states. While this is dimensionless, it is proportional to the volume because the number of quantum states increases as the volume increases (the spacing between energe levels gets less as the volume increases). So, you can express this dimensionless number as the volume divided by an effective volume VQ. Obviously the physical interpreation of VQ is the volume at which one particle would have effectively just one state available when taking into account the penalty in the form the Boltzmann factor that disfavours states with energy much higher than k T, so 1/Vq is the effective density of available quantum states per particle. Count Iblis (talk) 12:36, 22 May 2013 (UTC)

Teen Invents Super fast battery charger
Is this real? Can anybody shed some more light on this than the poorly written article? It seems highly unlikely that this girl has done what multi-bollion dollar energy companies cant (or just dont want to?)165.212.189.187 (talk) 17:27, 21 May 2013 (UTC)
 * Seems legit. Here is the original press release announcing her invention from the Society for Science and the Public and the International Science and Engineering Fair.  She won $50,000 for her efforts, and that doesn't seem like the kind of scratch someone just gives away for fun.  If you wanted the full details of her presentation or paper, I'm pretty sure you can contact that organization.  -- Jayron  32  17:37, 21 May 2013 (UTC)
 * As a side note, it does happen sometimes that rank amateur will invent something on their own, rather than a team of employees in an R&D department for some multinational corp. For as many Wallace Carothers there are in the world, there's likely as many Philo Farnsworth's; Farnsworth had essentially invented modern television in his barn at 15 years old.  Also, Steve Wozniak, Lee De Forest, Erasto Mpemba, etc. for examples of people who made significant scientific and technological advances completely independent of any large organization or corporation.  -- Jayron  32  17:44, 21 May 2013 (UTC)
 * Isn't Mpemba regarded as more of a quasi-mythological culture hero these days? Evanh2008 (talk&#124;contribs) 00:52, 22 May 2013 (UTC)
 * Erasto Mpemba is known for his student paper of the Mpemba effect, which counter intuitively says that warm water placed in a cold chamber freezes faster than cold water. Trouble is, his results appear to be based on faulty lab work.  Also, Steve Wozniak was a 26-year old engineering employee of Hewlett-Packard when he designed his first computer, which was not particularly innovative and certainly no engineering breakthrough.  Stories have been repeated about him single-handedly designed it at home, which given that there was no PC-based CAD at the time was certainly an achievement, but not a remarkable one. Wickwack 121.215.10.17 (talk) 01:03, 22 May 2013 (UTC)
 * Fine, forget Wozniak then. He did nothing of import.  I suppose that destroys my thesis that sometimes people can invent something at home.  I guess no one has ever done that.  -- Jayron  32  01:12, 22 May 2013 (UTC)
 * Not at all. You just picked a couple of poor examples.  A number of famous internet and cellphone applications were develoiped by teenagers at home.  As a competent Engineer I stand in awe of them.  Nor is Wozniack unimportant. In linking up with Steve Jobs, what Wozniack did later led to a profound change in how we think about PC's and what we expect of them.  Wickwack 121.215.10.17 (talk) 01:24, 22 May 2013 (UTC)
 * Not that it's on topic, but I verified the Mpemba effect under controlled conditions in 2006. It's very easily reproducible, and the fact that it's languished so long on the fringes of thermodynamics, almost like a piece of pseudoscience, depresses me. Not that it's on topic... Evanh2008 (talk&#124;contribs) 01:18, 22 May 2013 (UTC)
 * I tried to verify the Mpemba effect around that time too, but I failed to reproduce the effect. Perhaps my experiment was under less controlled conditions.     D b f i r s   07:46, 23 May 2013 (UTC)
 * That, or mine was. :) I don't think I'm even a scientist in the loosest sense of that term (unless "scientifically ambitious and with access to an industrial freezer" happens to be one of those definitions), so that may be the more likely scenario. It really seems like someone who knows what they're doing should have got a definitive answer by now, though. Evanh2008 (talk&#124;contribs) 07:51, 23 May 2013 (UTC)
 * I would be interested in how both of you did it - what experimental method you used. In Australia, we have on our ABC Radio, a Karl Kruszelnicki who has a regular national science program for kids and young adults.  I caught a braodcast of his some time ago where he answered a question on Mpemba Effect from listener.  I was skeptical and decide to do an experiment myself.  I immediately came up against the problem of how to define the freezing point and how to determine when it happened, given I had only a domestic fridge with a freezer compartment.  After some thought I decide to use a diode heater in each container of water.  The voltage drop across a semiconductor diode is inversly proportional to absolute temperature (about 0.5 V at 25 C depnding on diode and current, increasing ~2 mV for each 1 K decrease in temperature).  Passing a current thru the diode heats it.  Since the thermal conductivity of water is much greater than for ice, the point of bulk freezing (ie not a surface ice layer) is indicated by a relatively sudden small decrease in voltage preceded by a levelling off, part way thru a continuous gradual increase.  You can choose a very small diode and current such that the fridge can easily overwhelm the heat from the diode, and the temperature differential in the water/ice due to the diode is only about 0.5 K or less. I tried metal containers and styrofoam containers.  In both cases the cooler water froze first.  Wickwack 120.145.149.52 (talk) 10:57, 23 May 2013 (UTC)
 * You might check out the Slashdot discussion on the subject. Briefly, capacitors are not a new invention. They suffer from a couple of fundamental problems: their power density is tiny compared to batteries; and unlike batteries, their output voltage drops as you draw power from them. No fundamental discovery is in evidence here, more like what has been done before was demonstrated by an attractive young lady, which is catnip to popular media. 88.112.41.6 (talk) 17:53, 21 May 2013 (UTC)
 * She developed an improved supercapacitor using rutile titanium dioxide crystals which provides 238.5 Farads per gram, with energy density of 20.1 Wh/kg, and power density of 20540 W/kg, and a loss of about 1/3 the storage after 10,000 cycles. Pretty damned impressive stats, since Battery (electricity) says the highest energy density for present rechargeable batteries is 0.46 MJ/kg or 128wh/kg   See http://www.technewsworld.com/story/Teenagers-Power-Storage-Project-Lights-Up-Science-World-78085.html . Efficient circuitry to provide a constant output voltage to drive electronic circuits would be needed before we can throw away our celphone batteries and chargers. Maybe the idea is to dump energy into the supercapacitor in a few seconds, then charge the battery from the capacitor through some sort of voltage dropping circuit with an invertor, transformer, and rectifier. The putdowns of her just being a an "attractive young lady" who has done nothing special seem uncalled for. I also see websites where various anonymous persons are claiming first, that the energy storage device is noting special, and second that the real work must have been done by her parents or the professor.  That just makes them look envious. She showed quite a bit of initiative in contacting dozens of college professors with a request for the use of lab facilities  before she was allowed to use space at UC Santa Cruz. Edison (talk) 18:52, 21 May 2013 (UTC)
 * I tried to read our Supercapacitor article, but it seems to have been written by someone who is not fluent in English, as demonstrated by "All this first electrochemical capacitors used a cell design of two aluminum foils covered with activated carbon coins the electrodes which are soaked with an electrolyte and separated by a thin porous insulator implemented in a common housing." Anyone out there with an understanding of material science who could take the time to copyedit that article, which is both important and an embarrassment to the project? Edison (talk) 19:42, 21 May 2013 (UTC)
 * The article Electric double-layer capacitor largely duplicates what is in Supercapacitor, but gives a higher energy density for rechargeable batteries than does Battery (electricity). It says supercapacitors store up to 85 wh/kg, in a lab prototype. Ms. Khare's device might or might not scale up successfully. Edison (talk) 20:06, 21 May 2013 (UTC)

Melting point of a diamond
What temperature does diamond itself melt at? is it even possible for humans to melt? what device would be used to melt a diamond? Does it crack or burn first before it melts? Are there any scientific processes that involve the melting of a diamond? Thank you Horatio Snickers (talk) 19:28, 21 May 2013 (UTC)


 * You can't melt a diamond (or carbon in general) at any ordinary pressure. It sublimes rather than melting.  The lowest pressure where you can get liquid carbon, if the diagram is correct, is around 10 MPa, which is about 100 atmospheres. --Trovatore (talk) 19:33, 21 May 2013 (UTC)


 * (edit conflict) Read up on diamond and Carbon. At atmospheric pressures carbon - which is what diamond is - sublimes at about 3,900 K, ie.: it goes straight from a solid to a gas. At much higher pressures and temperatures it is theoretically possible to turn carbon into a liquid, see phase change diagram. WegianWarrior (talk) 19:51, 21 May 2013 (UTC)
 * Why do you say "theoretically"? 10 MPa is a lot of pressure and 4000 K is hot, but both are obtainable in the laboratory.  At least one of the refs in the carbon article has a title suggesting that the properties of liquid carbon have been experimentally measured. --Trovatore (talk) 20:01, 21 May 2013 (UTC)


 * Perhaps, because no one has tried? Plasmic Physics (talk) 21:06, 21 May 2013 (UTC)
 * If you read my last sentence, it appears that someone has in fact tried. --Trovatore (talk) 21:10, 21 May 2013 (UTC)


 * My appologies. Plasmic Physics (talk) 03:09, 22 May 2013 (UTC)


 * I noted something interesting about the phase diagram: accordingly, there is a narrow P-T range at which graphite can melt. The range appears to be from the triple point to somewhere between 0.1 and 1.0 GPa and less than 5 kK. Plasmic Physics (talk) 04:21, 24 May 2013 (UTC)


 * See http://www-als.lbl.gov/index.php/holding/276-time-resolved-study-of-bonding-in-liquid-carbon.html. Looie496 (talk) 22:54, 21 May 2013 (UTC)

Meowing of male and female cat
Is there a difference in meowing between male and female domestic cat, such as pitch, etc (assuming both are of the same age)?--93.174.25.12 (talk) 21:00, 21 May 2013 (UTC)


 * See Cat_communication for starters. Note that "A "caterwaul" is the cry of a cat in estrus (or "in heat")." --that is a very distinctive, loud, yowling call that only females make. As the article mentions, adult cats don't really meow to eachother, it is a kitten-to-mother call that got co-opted for cat-to-human communication somewhere in the domestication process. Anyway, aside from a cat in heat, my WP:OR is that there is a great deal of variation in meowing sounds among among individuals, with no clear sex-based differences. I have known some surly tom cats with tiny, weak "mew", as some with loud commanding "MEOOOW" -- and also the same for females. SemanticMantis (talk) 21:21, 21 May 2013 (UTC)


 * On average I would expect male cats to have deeper meows than females, since they are slightly larger and presumably have longer vocal chords. Of course, there will be exceptions. StuRat (talk) 00:26, 22 May 2013 (UTC)


 * Speaking purely impressionistically, but with a great deal of experience with cats, the males do tend to exhibit vocalizations of lower auditory frequency on average, but of course there is a great deal of variation; bear in mind that although all domestic cats belong to Felis catus by virtue of being able to produce viable and sexually productive offspring, there is a great deal of phenotypical differences between them, and the "voice" is no exception. That being said, the animal's size, health, and of course state of mind will all influence the tone of their meowing.  I will say that while I understand the point that Mantis is getting at, it is not entirely true that adults do not meow at each other - they indeed do it a great deal, even in feral colonies and other circumstances outside domestication -- they simple do it under generally different circumstances than the greetings or attention-grabbing (for example, feeding) purposes they use it for with humans.  Snow (talk) 01:19, 22 May 2013 (UTC)


 * I'm doing some digging for references, but so far this is what I came up with: This paper titled "The effects of articulation on the acoustical structure of feline vocalizations" seems to say, from the abstract, that the qualities of "feline vocalizations" is tied to the physical structures that produce those vocalizations, and that cats could be used as analogues for differences in human voices. While that does not directly answer the question, it does point in the following directions: differences in human voices are tied to differences in the structure of the voice-making apparatus in humans; that is the sexual dimorphism in human voices between males and females is directly related to the differences between the physical structures that make the voices in males and females and b) this paper indicates that similar processes may be at work in cat voices.  To make the final connection, we'd need to show that cats directly display the same sort of sexual dimorphism, which this paper does not seem to.  Still looking tho.  -- Jayron  32  01:45, 22 May 2013 (UTC)


 * Not cats, but rats: This paper titled "Rat 22 kHz ultrasonic vocalizations as alarm cries" states, in the abstract, that alarm cries in rats "show gender differences", that is you can identify a rat as male or female from its alarm cry. Again, not cats, but still, it does show that gender differences in voice is exhibited outside of humans.  If this has been done for rats, perhaps a study has been done for cats.  Still digging.  -- Jayron  32  01:50, 22 May 2013 (UTC)


 * No idea if it's a good match, but I did find This book, titled Your Ideal Cat: Insights into Breed and Gender Differences in Cat Behavior. Since it notes gender differences right in the title, it's a possibility it may cover meowing and other vocalization difference between male and female cats.  -- Jayron  32  01:57, 22 May 2013 (UTC)


 * Well, after an fairly exhaustive search through every subset of Google, I can't find anything one way or another. It seems that, with the notable exception of "caterwauling" (the calls of a female cat in estrous), there are not significant differences between male and female cats in terms of their vocalizations.  Or, at least, there is no evidence of anything in the literature to indicate such a difference (with the very important caveat that the absence of evidence is NOT the evidence of absence).  -- Jayron  32  02:11, 22 May 2013 (UTC)
 * Spelling note: estrous is an adjective; the noun is estrus.  I'll have to add that to my mental list of this particular spelling bugbear that gets a lot of people.  More common pairs to confuse are mucus–mucous and callus–callous.  Another slightly exotic one is phosphorus&mdash;phosphorous.  In each case, the word that ends in -ous is the adjective. --Trovatore (talk) 02:24, 22 May 2013 (UTC)
 * Mi scuso, mio amico... -- Jayron  32  02:29, 22 May 2013 (UTC)
 * That's normally mi scusi as one is asking the other to excuse, not forgiving oneself. μηδείς (talk) 04:49, 22 May 2013 (UTC)
 * Pardonnez moi -- Jayron  32  04:55, 22 May 2013 (UTC)
 * Actually I thought that part was fine. Scusarsi can mean to apologize.  Mi scusi (formal), or (more likely in this sort of exchange) the informal scusami, is a direct command, and these are more usual when talking to the interested party, but if you were talking to a third party in an high register, mi scuso col signor Trovatore would be entirely acceptable.
 * The part that didn't quite work was mio amico. Should be amico mio.   --Trovatore (talk) 06:43, 22 May 2013 (UTC)
 * I assumed Jayron meant to say "excuse me", (mi scusi); not "I excuse myself". You are right that either works grammatically and according to intention. In Spanish one might say deje que me perdone" (allow me to pardon myself), but perdoneme'' would by far more common. μηδείς (talk) 22:08, 22 May 2013 (UTC)
 * I don't know if the references unearthed by Jayron (well done!) mention this, but altered males (i.e. those who have had their testicles removed) will have higher-pitched meows than entire males, especially if the castration was done at an early age (4 months). OR - my male cat emits a higher-pitched squeak than either of my two female cats, and higher than my late male cat: I believe this is because he was neutered at an earlier age than my late male cat. In other words, castration has the same effect on cats as it does on humans. (No shit Sherlock, I hear you say!) --TammyMoet (talk) 10:10, 22 May 2013 (UTC)
 * I also wonder whether neutering alters the cat's voice, couldn't find an RS at first glance. 93.174.25.12 (talk) 11:23, 22 May 2013 (UTC)