Can a flammable gas ignite merely by increasing its temperature (without a flame)? | AskScience Blog

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Friday, April 29, 2016

Can a flammable gas ignite merely by increasing its temperature (without a flame)?

Can a flammable gas ignite merely by increasing its temperature (without a flame)?


Can a flammable gas ignite merely by increasing its temperature (without a flame)?

Posted: 29 Apr 2016 12:37 AM PDT

Let's say we have a room full of flammable gas (such as natural gas). If we heat up the room gradually, like an oven, would it suddenly ignite at some level of temperature. Or, is ignition a chemical process caused by the burning flame.

submitted by /u/ExCx
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Why do biologists always refer to mitochondrial DNA in reports on evolution and cladistics as opposed to the DNA found in the nucleus?

Posted: 29 Apr 2016 12:33 AM PDT

This might sound like a rather stupid or silly question but I just though about this while studying for my IB bio exam.

submitted by /u/littlewigbighair
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How does fracking affect volcanic eruptions?

Posted: 28 Apr 2016 06:39 PM PDT

I was thinking, if it triggers earthquakes, wouldn't it also maybe make volcanic activity more likely?

submitted by /u/zeldazonklives
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If transcription and translation are coupled in prokaryotes, how do mRNA quantification methods provide meaningful results?

Posted: 29 Apr 2016 12:40 AM PDT

Wouldn't it be more of a measure of the brief latency between transcription and translation than an indicator of transcript or protein level?

submitted by /u/neurominer
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Do all of the planets orbit on the same level, and if so why does it appear that we're "looking up" at Saturn through Earthbound telescopes?

Posted: 28 Apr 2016 06:50 PM PDT

Are there dynamic weather-like changes in Saturn's rings between daylight and planet shadow?

Posted: 29 Apr 2016 12:21 AM PDT

I know the concept of "weather" in Saturn's rings isn't the right way the phrase the question, but that's really where this line of thought comes from. Do Saturn's rings experience weather? I was thinking that there must be a difference in temperature between when the rings sit in Saturn's shadow and when exposed to sunlight. I know it's darker and colder out there than here in the comfy habitable zone but is the fluctuation between warm and cold enough to cause dynamic weather-like patterns in the rings?

submitted by /u/porty_paisley
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Will continental drift eventually bring the continents back together?

Posted: 29 Apr 2016 04:50 AM PDT

Is water at absolute zero denser than water at 4 degrees Celsius?

Posted: 28 Apr 2016 03:36 PM PDT

I know liquid water is generally denser than ice from the polarity of the bonds, and the way the molecules orient themselves, but as things approach absolute zero they get denser and colder, so is there a point where ice surpasses the density of 4 degree Celsius water?

submitted by /u/Arabaster77
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Why are spinal discs so prone to hernias?

Posted: 28 Apr 2016 08:37 PM PDT

I'm a 1st year med student, studying the lumbar region in anatomy, we barely brush on the subject and the professor wasn't able to give me the answer I was looking for.

So, throughout the millions of years of evolution, how come the spinal discs are STILL so prone to hernias and bulges? I mean, it was enough for me to pick up weights in an incorrect way to herniate my L5S1 (CT+MRI approved) as well as billion of others who suffer from a similar condition.

submitted by /u/Xeydo
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Can EM field bend light?

Posted: 28 Apr 2016 07:43 PM PDT

Is there a mathematical proof/justification for x^-1 = 1/x? Or is it just conjecture/nonclemature?

Posted: 28 Apr 2016 06:53 AM PDT

The inside of my pineapple can appears to be galvanized steel, what is the reason for this?

Posted: 28 Apr 2016 01:53 PM PDT

Some quick searching online suggested that galvanized steel might not be all that food safe since the zinc coating can end up in the foodstuffs if they are acidic. Some also suggest that there is a lining between the steel and food, but if so then why bother with a galvanized steel can instead of a typical can?

submitted by /u/thar_
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Why are radioactive elements that only give off alpha radiation still dangerous, given that that's just a helium nucleus?

Posted: 28 Apr 2016 09:48 AM PDT

How much does quantum uncertainty effect the macro world?

Posted: 28 Apr 2016 01:56 PM PDT

Why is it that you can put so much weight on one side of a barbell without it tipping over?

Posted: 28 Apr 2016 06:13 PM PDT

I was at the gym today and I was able to put 90 pounds on one side of the barbell without it tipping over. Why doesn't any imbalance of weight cause it to tip over?

submitted by /u/CashCop
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Is it possible to choose a wedding date that has the highest probability of me actually being there?

Posted: 28 Apr 2016 04:22 AM PDT

I work on a ship in a cycle where I am away for an average of 80 days, followed by an approximately equal length holiday where another person works in my place. I am newly engaged and hoping to get married in February 2017 but due to my work trips being not of an exact length it is very difficult to choose a date and start making bookings/invitations. Here are my previous trips:

28/07/2014-09/10/2014 73 days

09/10/2014-26/12/2014* 78 days

26/12/2014-05/03/2015 69 days

05/03/2015-29/05/2015* 85 days

29/05/2015-20/08/2015 83 days

20/08/2015-03/11/2015* 75 days

03/11/2015-26/01/2016 84 days

26/01/2016-25/04/2016* 90 days

Trips with an asterisk represent when I was on holiday but are equally valid trip lengths in terms of data because the ship does the same journey.

I am on the ship now and my most recent trip began on the 19/4/2016. This is earlier than the end of the last trip because our records only show departure time so I took the dates from departure-departure and will work them back to the day I joined. I will do this work trip, a holiday, another work trip and then we will get married in the following holiday.

If we want to get married on a Saturday what is the best date to choose? We understand that this is a basic mathematics problem however the answer is very important to us for obvious reasons. Thank you in advance.

submitted by /u/boobsandsandwiches
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Why is it still impossible to manufacture Water?

Posted: 28 Apr 2016 10:09 AM PDT

Maybe a really stupid question, but, out of everything we are technologically capable of doing I don't have a wide enough knowledge of science to understand why we can't just "make" water. H2O seemed oh so simple in high school science.

submitted by /u/house221b
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Why didn't this mixture of Conc. Sulphuric Acid and Cyclohexane react as expected?

Posted: 28 Apr 2016 12:21 PM PDT

Hi! British 6th form student here. So in chemistry earlier, reasons aside, we were mixing concentrated sulphuric acid with cyclohexene, and we got the expected result once, a orange mix. However, when we first tried the reaction a gas was produced, (known because the bung popped off spectacularly), and we got a black stodgy mixture with a slight orange tint,. However, when put into water it took on a slight greenish tint, and behaved strangely, some floating at the top, some going to the bottom, some strands going inbetween the two. I would guess that there may have been a contamination in the test tube, but that is fairly unlikely as it was a fresh batch of clean test tubes. Can anyone identify what it is that has happened here?

Sorry about the picture quality, best i could do at the time.

/u/superhelical has kindly pointed out to me that I was wrong, and that when I wrote cyclohexane I meant cyclohexene. So, hats off to him, and sorry about my mistake.

submitted by /u/JGAJ99
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How to reconcile clocks in simple time dilation problems?

Posted: 28 Apr 2016 08:01 AM PDT

I think the answer here is going to be pretty straightforward, but I can't find what I'm looking for in the FAQ or by searching. I think my confusion might go a bit deeper, but I've boiled things down to a simple problem that I can't quite grasp. Got to be something simple I'm missing.

Let's say there are two spaceships, both 6 lightyears from Earth in opposite directions. The ships and Earth have their clocks synced and have no relative velocity. Both ships accelerate quickly to 0.6c towards Earth and stop when they arrive. From the reference frame of Earth, it will take 10 years for both to arrive. The Lorentz factor for 0.6c is 1.25, so when we look at the clocks on board they'll say 8 years have passed. So a person on Earth was correct to believe that the spaceship clocks tick slower.

Confusion: shouldn't the observers on the ships perceive time passing more slowly on Earth and (even more so) on the other ship?

Let's say ship A assesses the situation after accelerating (instantaneously). Earth is 6 lightyears away and coming closer at a rate of 0.6c. Ship B is 12 lightyears away and coming closer at a rate of 0.88c (by velocity addition with relativity). That gives a Lorentz factor of 2.125. This means Earth should reach A after 10 A years (6/0.6), while only 8 years (10/1.25) passed on Earth. And it means B should reach A after 13.6 A years (12/0.88), while only 6.4 years (13.6/2.125) pass on B.

Obviously this second set of calculations makes no sense. It seems clear from the problem that B and A should reach Earth at the same time.

And it's also confusing that the clocks don't match up. I expect that part of the problem is the "broken symmetry". The ships accelerate and Earth doesn't. But with my understanding I get the same confusing results if you remove this aspect. Toss out Earth and the problem should look the same either way, no? Yet each ship thinks time passes differently on the other ship. So how can their clocks match up in the end?

I've tried drawing some Minkowski diagrams to make sense of things, but it's not helping. I assume my misunderstanding is either carrying over to that exercise or else it's deeper than I think.

Can anyone help me out here?

submitted by /u/jofwu
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We evolved from monkeys, could it happen again given enough time? Could another species/family/genus of homosapiens occur?

Posted: 28 Apr 2016 05:32 AM PDT

Could we see/co-exist with another "group" of humans?

submitted by /u/SahSon
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Is the infinite-th root of -1 equal to 1?

Posted: 28 Apr 2016 05:11 PM PDT

Using polar coordinates to work out powers and roots on an imaginary/real plane means that to raise a complex number to a power, the new angle become the product of the power and the angle, and the new r (distance to the origin) becomes rpower

-11/2 shows that you get i (or -i but lets just deal with positive roots for now), raising it to a third makes the root move closer to 1 along the unit circle. It gets even closer for a quarter. summarised visually here

Does this mean that as the power approaches infinity, the root approaches 1? Can you therefore infer that 1 (as absurd as that alone sounds) could equal -1?

submitted by /u/YesmynameisPerry
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