34 thoughts on “Make your coffee with a laser

  1. Of course this is not a hack. Why, it says right on the original shipping box from my 2 kilowatt laser that it’s also good for heating up hot beverages. It’s actually designed for this! Can’t y’all find something better to link to? ;-)

  2. okay,
    so every cup is lit for, like 19 seconds..
    2,5 kW = 2500 Watts.
    1 Joule = 1 Watt * 1 Second.
    so there’s 2500W * 19S = 47,5 kJ thrown into that cup.

    for 1 liter of water, you need 4,2 Kj to heat it up by one degree Celsius.

    so say there’s 100 ml water in that cup, that’s 0,1 L.

    so you need 0,42 KJ to heat it 1°
    0,42 / 47,5 = 113°C
    if the cup was at room temperature, the coffee would become 135°C.

    so you’d vapourize like half of it..

  3. Somehow I dont think the coffee was heated up in a perfect conditions so theres going to be a large amount of heat lost to the environment. The figures are perfectly reasonable when you take in the (normally large) losses.

  4. Also, there could be more than 100ml of water in the cup. 200ml wouldn’t be unreasonable.

    Also, the water could be cold from the tap, so less than room temperature.

  5. Answer to thijs:

    Its not that simple that when water gets to 100 degress celsius. it just vaporizes.

    It takes a fair share of energy to change its state from liquid to gas.

    It´s one of the basics you learn in physics.

  6. ND YAG? cool, but I thought those only put out infrared, 1100nm or so… Why’s it blue? The only way I can imagine it going to blue is if you used a non linear crystal to half the wavelength, but those aren’t very efficient and you would not get anything near 2.5kW and it’d take much longer to heat up the water…

  7. It’s mostly white because of the IR bounceback from the cup being detected by the camera. The blue hints you see are the spectrum of water showing up as the water directly in the beam’s path drop energy levels. (Sky is blue reasoning).

  8. sweet hack, I love lasers.
    A YAG laser outputs 480nm light which is a blue ish color. They also had to put so much energy 42kJ into the cup because there is a lot of energy reflected of the liquid ( thats also why the cup is white otherwise it would be vaporized)

  9. Well, a hack IS taking one thing and using it for a much cooler purpose, at it’s core, so this is a hack. We need more people willing to do crazy shit like this with lab equipment, whose cool abilities are normally squandered for private science.

    Since it seems a fair bit of you seem to know a lot about lasers, I got a ? for you: How does distance from the origin of a laser beam affect it’s cutting abilities? You always see industrial lasers cut close up- what is it about the properties of a laser (the power?) that seems to drop drastically with distance? Is there a way to calculate this? I have searched. What are the factors?

    Also, I know laser light can be colminated to round the beam profile more, but can a laser be MAGNIFIED? Can the effective spot diameter on, say, a 60 mw laser be passed through a magnifiying glass/lens to concentrate it’s power, possibly to cut something?
    I’ve just never seen anyone do it, it is light, so it should be possible…?

    Thanks to anyone that knows anything.

  10. couldn’t this easily heat the water/coffee into a supercritical state? i kinda expected that water to violently boil once he put that teabag in at the end.

    @15, of course you can focus laser beams, thats why it’s dangerous to our eyes, since the lens inside the eye concentrates the beam to a tiny spot onto the retina. you will need a lot more than a 60mw laser to cut through metal though ;-).

  11. seemed very cool… until i watched it. i thought i was going to see ZAP! and the coffee is done. i could have got a tea kettle whistling before that terd broke off.

    not nearly as practical as good ole’rf, for sure. here’s an excerpt from howstuffworks that should shed some light(har har) on the subject:

    “microwave ovens are popular because they cook food in an amazingly short amount of time. They are also extremely efficient in their use of electricity because a microwave oven heats only the food — and nothing else.”

    see, the microwave oven was invented in 1947. the first laser demonstration not until 1960. and now, in 2007, the laser, with all the experimentation and study, still cannot compete in this regard with a 60 year old invention that has remained basically unchanged since it was first put on the consumer market.

    what i’d like to see is someone cook an egg utilizing nothing but 2 cell phones and an fm radio. not this BS “we used a laser to make stuff hot.”
    very innovative, i’m sure.

    come on, guys. we want stuff that makes life easier, not harder.

  12. @15, from what i know the cuting abilities of a laser are mainly dependent upon:
    - power and type of laser used (NdYAG or CO2, depending on what material you need to cut)
    - diameter of the unfocused beam
    - beam quality (gaussian beam is ideal, etc.)
    - focal length
    - depth of focus
    I’m a student and some of my lectures have covered the basics of laser cutting. There are many experts out there though, so hopefully they can either confirm or correct this.

  13. You all are some downright arses. I agree with eliot, this is a cool demonstration of a laser’s abilities. I mean, who doesn’t want a 2kv laser at home? :)


  14. The beam appears blue under the camera because cameras don’t know how to respond to IR light. They try to filter as much as they can out, but what does get through usually ends up in the red or blue detectors in the camera.

    Nd:YAG only lases at ir wavelengths, the strongest line is 1064nm (that is what this one operates at, it is shown clearly at the beginning). To get the blue/green/red lines you use one or more nonlinear optics, q-switches, opo’s, etc.

  15. As we all probably know, the definition of “HACK” is dicey and debatable at best—but using LASERS to heat COFFEE??? Now, in my opinion…anybody who does not agree that cooking coffee with lasers is a cool hack needs to turn in their tools and hang up their soldering iron.

    on a 1-10 i give it 7 and a half stars with honorable mention of “high coolness factor” but only 7.5 because i dont like coffee. Still its a bit improbable that the average “hardware hacker” will ever get to test this with his (or her) own laser but, cmon! lasers that do ANYTHING besides LOOK cool (which they do very well) including but not limited to ray-guns, light sabers, laser pointers, laser copiers, and YES even laser-coffee makers. are very, very cool. Making lasers do anything different from what they have done in the past is righteous by Mr Jones’ standards……now post some youtube of it cooking a muffin and an egg and a slice of sausage and post the first ‘Laser-cooked egg-mc-muffin” video and ill give you a 9.5 stars!


  16. Re: laser vs microwave heating.

    the average kitchen microwave will take upwards of 2 minutes to heat a cup of water like those shown to boiling. This laser did the same in roughly 18 seconds. I say the laser wins that speed competition.

  17. yeah, i know. i mean, we’re comparing a boring old microwave oven to a frickin’ laser! by my count, though, the time(starting from the time they pushed the button that says, “go” to the time that the water boiled over) was about 25 seconds. nearly half the time that it takes for a decent microwave(not the one that’s been in your mother’s kitchen for the last 20 years) to heat up a cup of water to a good degree for coffe drinking. now consider the time it takes for that boiling water to cool down enough that a human can drink it without seriously damaging his flesh, then we have an obvious winner. not to mention all that energy wasted with the laser has a direct effect at the gas pumps.

    that laser “hack” is not nearly as practical as you try to make it seem. in theory, lasers are definitely cool. put to good use, such as eye surgery, the absolute coolest, but any 4th grader could tell you, yes, lasers can make water hot. it’s to be expected. this demonstration was just completely lacking in any WOW factor and a microwave is so much more efficient and practical. if the purpose is to show how to move backwards, though, these guys hit the nail right on the point.

  18. Coffee with less then a spoon full of granules. Weak…. i thought sciency people would at least have 2 spoonfulls. what was in that jar wouldve done 2 cups max…

  19. Gotta take into account heat losses to ambient, and also to the cup. Though the laser wasn’t heating the cup, it was heating the liquid, and via conduction heat was transferred to the cup. Also different materials have different heat densities-water holds a LOT of heat. Hence being used in nuclear reactors as coolant, steam plants for heat/electricity/propulsion (like subs and carriers), orange groves to prevent freezing, etc.
    The heat/energy required to push water over that limit to boiling (thus a ‘saturated system’) is quite a bit. I can’t remember exactly the equations…learned them ages ago in nuke school.
    Oh, that’d also explain why the water didn’t ‘explode’ out of the cup when he put the teabag into the water-wasn’t superheated. Under normal conditions, water will NEVER exceed 100 c, unless the water is distilled so that there ar no impurities and the cup/container is absolutely smooth, so that there’s no surface for steam bubbles to effectively form. Only under those conditions…or increase the pressure of the system.
    Hope that answers questions.

  20. While you guys are all wondering about the state of the coffee…

    I’m more curious whether or not those guys are still employed there.

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