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Flame Tube 2012

I love teaching high school physics, and one of my favorite demonstrations every year is the Ruben's Tube I've made to show my kids a visual representation of sound waves.

Basically, it's a long metal tube with holes drilled in the top. I've got gas (propane works well) running through the line, which ignites when lit. I put the subwoofer of my speakers up in front of one end of the tube (which is blocked off with a soft membrane) to send vibrations into the tube. The vibrations of the low notes change the pressure in the tube, which changes the height of the flame.

Flame Tube 2012
Armand Salmon's profile photoSwaroop Subbanna's profile photoKelli Seeger Kim's profile photoJeff Moreau's profile photo
I knew that what was what you were doing!! Cool!
I assume you also attach a signal generator to pump in various sin frequencies?
Glad you liked it, +John Getchel :)...

I've tried sending individual frequencies through the line via a wave generator but honestly it doesn't produce very good sine wave with my current setup. My subwoofer transfers the low frequencies through the soft membrane (a balloon), but none of the higher frequencies. I think I'd need to affix one of the mid-range speakers to the actual end of the tube to make those frequencies move the wave.
Very cool, +Jeff Moreau! Like I've said before, you would have been my favorite teacher. :)
It was long ago that I saw it but it may be a function of the size of the tube but I have seen examples where node and anti-nodes are quite visible.
Aw thanks +Tisha Craw :)

Yeah +John Getchel ... I show my students a few video examples of those after this, but they are always done with speakers that are directly hooked up to the edge of the tube. I bring my computer speakers from home for this, but some year maybe I'll get some speakers that I can permanently hook up to the tube for more options :)
Omg I totally went back to high school now ... My physics teacher always had great demonstrations. I remember that I use to dislike physics but after having him as my teacher I changed my mind. Awesome +Jeff Moreau
I loved physics, except sometimes I would forget some of the formulas (o: I saw a ridiculous demonstration like this one and I am now trying to remember what song it was.
What if I told you that I give my students the formulas, +Sharon Strandskov?... would that remove some of your hangups?

Let me know if you find that demonstration!... I always love a good physics video :)
Yes! (I do get that if you really understand the concepts, the formulas are easier to figure out without needing to remember them... but that takes time)
I teach middle-level classes for students that mostly aren't going to have physics again after they graduate high school. I figure if they really need an equation later in their life they can look it up. They need to know how to use the equations, what the variables stand for, and which ones are appropriate... but I don't see the long-term necessity to have them memorize all the equations.
Oh, totally... that was my point. If you don't know physics well enough to be able to figure out the formulas based on the concepts, you should be provided them. Memorizing does no good.
This is interesting and a great demonstration +Jeff Moreau ... on top and more important of all ... is that you are a great teacher man!! I never ever saw this in High School.
:-D... a lot of physics teachers don't agree with me, but I don't need them to. I'm glad you agree, +Sharon Strandskov :)
Thanks +Ricardo Williams ! :)... it's always fun for me to do this one. Any excuse to combine music and fire while getting paid sounds great to me.
You got great music taste, too.... Nice project, you should create some sort of dancing fire place....
Physics is the mother of all science!!
Well and in order to derive the equations you need second year calculus. Most high school students won't ever take calculus. A sad statistic...
+Jeff Moreau - You are too cool for words. Now if you don't mind, I'm pulling out a couple of skewers for some hot dogs and marshmallow, while I'm doing the jiggy. :D
Thanks, +Tom Tran ! :-D...

I like the way you're thinking... I need to craft one of these for a barbecue some time. If I do that, though... you can almost guarantee that I'll be jumping over it and limbo'ing under it (but not at the same time). I was very seriously contemplating leaping over this during the video, but... I didn't trust myself to fully clear it in my dress clothes/shoes, and I wasn't going to start stripping in my classroom.
Yeah, I'd hang in there (no pun intended maybe ) until the school year is over before any stripping in the classroom. Mr. Moreau. :D
Haha, I'll be sure to heed your advice, +Tom Tran ! :)... I think it's best if I want to insure my job security.
Whoa, this is like the Prometheus visual Equalizer. ;)
I have an admiration for what you are doing. Igniting that spark in your students with some creative teaching. Way to go man.
You're right +Armand Salmon ... it's pretty much a physical visualizer... with fire! :-D

Thank you :)... I really do enjoy what I'm teaching, so that makes it so much easier to get into it and get excited about it.
Thanks +Swaroop Subbanna ! :)... I always have fun with it and I hope to keep improving it as the years go by. Glad you liked it!
And sorry about the little +1 bomb earlier Jeff ;) I had missed pretty much everything that you had posted this week I think, what with me going to work early and you posting stuff in the mornings :)
You never have to apologize for a +1 bomb, +Swaroop Subbanna !... I was delighted to see it. I was out most of the past 2 days, so I'm a little behind on what has been going on with G+, myself. I hope to sit down and catch up in a little bit :)
:) That's what I've been doing since morning today. Need to get off my ass and get myself some lunch. LOL :)
:)... I have fun with this one every year, +Kelli Seeger Kim ... and I have a big dumb grin on my face as I blast my music with the fire... and I'm getting paid to do it!
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