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Lasers and Sodium Metals.

vortish

vortish

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Hey guys:


I kind of had a weird Idea :huh: pop in my head today.. We know that Alkali metals reacts violently when put into water.. I am talking about sodium, magnesium, and others of that family.. Has any one ever tested what a 3 watt laser would do to these elements... I know that if you put sodium in water it has a very violent reaction I am wondering if being subjected to that much thermal radiation it would just burn or would it have a reaction of some sort... I know many of you are thinking this is a troll or just a stupid question. But I really am curious to see the reaction as I currently do not have or have access to a 3 watt laser in any nm or sodium metal so just a nutty idea i guess..
 





C

CheeseHasLeafs

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Alkali metals are reactive cos they lose a valence electron. I suppose a UV laser of some sort could knock it off. I doubt a laser, even 3 watts, would do much to it though. Most of it would just reflect off.
 
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IsaacT

IsaacT

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Hmm...would be fun to try, but you need to get it into a dry environment.
 
busman2

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I tried it with some magnesium tape but nothing, zilch! I do have some Magnesium powder so might try that, most that could happen is to burn a hole through my floor, right? :)
 
ryansoh3

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Lithium, magnesium, calcium and other period 1/2 elements burn very brightly.

Maybe a high powered laser can heat them up so they undergo rapid oxidation?

 
styropyro

styropyro

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I would think it would be pretty difficult to ignite a piece of sodium or magnesium with a laser. For one, metals are pretty reflective so it would be difficult for them to absorb much light radiation. Also, metals are highly thermally conductive, so the light energy absorbed and changed to heat energy would quickly get pulled away unless you were heating a small sample.

That being said, if you got the metal hot enough with a laser, it would burn just like you had lit it with a flame. Sodium burns in air with a bright yellow flame to yield an assortment of products. I wouldn't recommend igniting sodium without lots of safety gear though!
 
paul1598419

paul1598419

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Use magnesium shavings, like in the old flash bulbs for Polaroid cameras. That should get you the reaction you are looking for. Sodium metal, not so much. You need a proton, like you can get from water, to start the reaction with sodium.
 
styropyro

styropyro

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^ I'd actually expect sodium to ignite easier than magnesium in air. Sodium does not have to be participating in a Lewis acid/base type reaction to get going, it'll happily burn in oxygen to form different sodium oxides.
 
vortish

vortish

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there are many metals with in the family mag, sodium, potassium are the most reactive with air or water but there are others with in this family this was just a thought is all and you guys are making a lot of good sence
 
paul1598419

paul1598419

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While it's true that sodium metal doesn't have to participate in a Lewis acid/ base reaction, that's why it is kept under oil, it doesn't spontaneously combust in air, either. It will slowly oxidize in the atmosphere, unless there is the addition of heat and or pressure, or especially condensation, ie. water.
 
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Sigurthr

Sigurthr

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Unfortunately being metallic it doesn't absorb light well, not even 10.6um heat. 15W isn't enough to get it to burn. It is easy to ignite using the heat from an exothermic chemical reaction though; beautiful 589nm flame! [Talking about Sodium here, btw.]
 
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paul1598419

paul1598419

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Magnesium doesn't combust in water at all. Anyone who has finished organic chemistry should remember the Grignard reaction. It isn't even easy to get it to react under these conditions, usually needing fresh cut unoxidized Mg and some heat to get it started.
 
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