Hi guys,
They made one mistake in the blogs: the laser DOES work with exhaled breath only!!! I wish they had clarified this. I don't remember ever saying that it required Helium and N2; only that it was lasing on exhaled breath.
To be sure; I've tried both exhaled air into a balloon and exhaled air with helium. No surprises here, but helium does significantly enhance the performance. Irregardless, it is quite possible to get a reasonable laser with exhaled breath alone! IIRC, there was no helium used for this video. Since the video was made, I added this device to the system in order to make the output more steady and reliable ...
pressure-regulators on Flickr - Photo Sharing!
The balloon is used with all gasses. Not just exhaled air. When using CO2 from another source, such as mixing baking soda and vinegar, I use the following precedure to obtain a predetermined mix:I first deposit a small amount of CO2 into the storage balloon (hereafter abbreviated as SB). I measure the circumference of the SB using a tailors measuring tape, and then use this circumference to calculate it's volume. After considering the volume of CO2 that the SB contains (I want the CO2 to be about 10% of the final mix), I decide how much N2 I want in the mix. If I want roughly twice as much N2 as CO2 in the final mix, then I add this corresponding volume to the volume of CO2, and calculate a new circumference (in other words, 3x the volume of CO2, which I originally calculated). I then fill the SB with N2, until I arrive at this new circumference. At this point, I divide the sum of the two volumes by 30% (assuming I have twice as much N2 as CO2), and then calculate a final circumference using this number. Following this last step, I inflate the balloon with helium until this final circumference is reached. In this way, the 3 gasses can be combined in a predetermined ratio with some accuracy. Sure - the balloon is not a perfect sphere, but this method is much more accurate than simply guessing!
The original video is here. I have a description below it.
YouTube - Homemade Carbon Dioxide Laser Running on Exhaled Breath!
- Jarrod