Two-killowatt laser heats coffee, wows onlookers
By Darren Murph 
posted Mar 25th 2007 5:30AM
posted Mar 25th 2007 5:30AM
Lasers have found their way into the hearts of modders everywhere, and while this latest case doesn't guide missiles or remove hair, it does make a mean cup of joe. All you'll need is a sturdy mug, coffee grinds (or a tea bag, whichever you prefer), a bit of water, and a spare two-kilowatt laser to get things a steamin'. Sure, there's most certainly a few alternatives to accomplish this same task with a lot less hassle, but there's just no substitute to making your office a round of java with a commercial-grade laser. Now, how about we give this a go with a 67-kilowatt version? Click on through for the vid.[Via Hack-A-Day]
Sweet.... coming to a kitchen near me?
It will come to a kitchen near you when you can find someone that's willing to fork out hundreds of thousands of dollars. High power lasers are still very expensive.
Does using the laser increase the risk of free radicals in their coffee/tea?
For immediate release:
SEATTLE - Starbucks Inc. readies their new weapon in the caffiene-delivery battle arsenal: the laser-guided half-caf quad venti raspberry organic no-whip white mocha.
It looks like the coffee is being "beamed up".
This is news? This can't be the first time in history someone has heated water with a big ass laser in a lab.
Yes, but it's obvious that you would have pointed to a link if you knew of someone who did heat up water with a laser in a lab so it is (new)s to you =).
- Tony R.
Not at all. It is so obvious looking it up would be a waste of time. :)
How on earth can you call that Nescafé-thingy coffee? And especially when you only take something like a half of a teaspoon of it?
BTW, they should have used a better brand of coffee and I would have been really impressed if they could have rigged up a mirror system that could heat up all 4 cups of coffee at once (maybe putting the right grade mirror at the bottom of the cup that would then bounce to another cup with another such mirror, etc).
Just my two cents, I just wish I had something stronger than a laser pointer o.x.
- Tony R.
As the cups seemed to hold up quite well under the laser fire, does this mean that they will eventually become standard military issue in battlefield situations?
what the hell was that?
According to my calculations, the effective power output was 936 watts.
* Assume the cups are 8 ounces, which is ~237 cc of water
* Water has a specific heat of 1.0 -- it takes 1 Joule to heat it 1 degree celsius per cc
* That's 237 Joules per degree celsius
* Room temperature water = 21 degrees celsius, boiling = 100, so that's an increase of 79 degrees celsius
* 79 degrees Celsius * 237 Joules per degree celsius = 18723 joules to heat 8 ounces of water to boiling.
* The light was lit for 20 seconds on the first cup
* 18723 joules / 20 seconds = 936 watts
Possible sources of error:
* Incorrect estimation of cup size
* Water was not room temperature coming from the tap
Possible sources of lasing inefficiency:
* Inefficiency in the laser
* Reflection of light off the water
* Loss of heat due to convection at the top of the cup
* Frequency of laser was not tuned to the absorbtion frequency of coffee (water ~= 2.4Ghz)
* Probably lots of others since I know nothing about lasers :-)
Heh, what you forget is the steam! As the water heats in a non-uniform way, some of it will evaporate before the average temperature reaches 100 degrees. Phase-change needs lots of energy compared to heating, and thus most (or half, according to your calculation?) of the energy is lost.
Cheers!
You don't boil water to make coffee. That results in scalded coffee. Idiot
Possible sources of error:
1) Your numbers are incorrect. The specific heat of water is 4.186 Joule per gram degree celcius, not 1. You are thinking in terms of calories.
2) Also, the laser they were using was most likely an industrial CO2 laser (which is QUITE efficient, might I add), with a mean wavelength of about 10 micrometers, which translates into a frequency of about 30GHz, so the laser is not exactly at microwave frequency, but close enough.
3) Your possible "source of error: Reflection of light off the water" is complete nonsense.
I see a potential application in the vending machine of the future...
Of course they would have to get rid of the Nescrappie that they used in this prototype...
Now all we will need is an industrial robot with a special attachment to grind up the beans...
Bob
No, that's incorrect because I don't think the coffee was heated all the way to boiling point.
@ Moby Disk
Actually the source of error is your calculation. The specific heat of water is 4.194 J/ºC. Your calculation is for calories not Joules. So assuming the rest of you math is correct then, the correct # of watts is 3916. Also, if you noticed, the cups are not full.
-Ted
instant coffee? oh, dear god no. =/
How does the coffee know if the water was boiled?
Finally, a coffee that will cost more than the ones in Starbucks.
Makes you Wonder what is more Energy Efficient, A coffee maker running for 30+Minutes or the Laser for 20 seconds heating the coffee?
Nescafe? GROSS