Morning can produce dramatic blue bubbles, and Grand can produce small ones as it starts bursts (particularly the first). All that's happening in a blue bubble is that the surface of the geyser's water column is being lifted (usually by a rising steam bubble well below it in the column) without breaking it. Surface tension holds the water together in a dome shape until the surface is stressed beyond its ability to hold its shape, or, more commonly, until the steam bubble reaches the surface and breaks it. The color is blue for the same reason that clear pools with white walls appear blue--scattering and/or selective absorption of visible light. David Schwarz <div class="gmail_quote">On Mon, Jul 5, 2010 at 2:25 PM, David Monteith <<a href="mailto:dmonteit@comcast.net">dmonteit@comcast.net</a>> wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">It took a couple extra days to send this message from Janet Chaapple because I was out of town and didn't have access to the software I needed to reduce the size of the original image. Dave From: JOChapple <<a href="mailto:jochapple@earthlink.net">jochapple@earthlink.net</a>> To: Geyser Observation Reports <<a href="mailto:geysers@lists.wallawalla.edu">geysers@lists.wallawalla.edu</a>> Subject: Strokkur Geyser Date: Sat, 3 Jul 2010 09:08:08 -0700 For those of us who can't make it to Yellowstone this month, here is a slight diversion courtesy of my son-in-law, Niklas Dellby, who returned from a trip to Iceland in mid June. I asked him to forward me his picture of Strokkur and also the URL for his brief YouTube video of two eruptions a few seconds apart. I didn't know before I saw this that Strokkur has blue bubbles, not unlike the best of Great Fountain's. Can anyone tell me about other geysers that produce blue bubbles—and do you scientists out there have an explanation for them? The YouTube URL is: <a href="http://www.youtube.com/watch?v=RXXFKRuWWLM" target="_blank">http://www.youtube.com/watch?v=RXXFKRuWWLM</a>. There are several other Strokkur videos at the same site with even more beautiful eruptions. The bursts last from 3 to 5 seconds each. Janet Chapple _______________________________________________ Geysers mailing list <a href="mailto:Geysers@lists.wallawalla.edu">Geysers@lists.wallawalla.edu</a> <a href="https://lists.wallawalla.edu/mailman/listinfo/geysers" target="_blank">https://lists.wallawalla.edu/mailman/listinfo/geysers</a> </blockquote></div>