Odds and ends

[Mark]

I was reading some old literature I have, a few pages copied out of a book entitled "Generation and Measurement of Sound in Gases" by R.W. Leonard.
There is mention of using sirens that produce intensities to cause cotton to busrt into flames by the absorption of acoustic energy. It might be kind of interesting to see.
Here's some tidbit I dug up on the net.
"Izzy loved to use demonstrations in his teaching. His public lectures at UCLA, given under the title of “An Evening of Demonstration Experiments in Physics,” where always standing room only. He would levitate objects in high-intensity sound fields and make cotton burst into flames as it absorbed the abundant acoustic energy generated by his siren. Though simple in appearance, these demonstrations included fresh discoveries, which quickly became part of the curriculum because, as Izzy put it, “Today’s research is tomorrow’s homework.”
http://www.universityofcalifornia.edu/s ... sadorerudn...

Silent sounds are hot
http://books.google.com/books?id=RigDAA ... re&f=false

[Mark]

These might be useful or fun to play with for some pulsating combustion valved device or other exotic uses.

Advantages of Machined Springs:
Quality-reliability
Repeatability-predictability
Precision elasticity
Integration with the entire product
Reduction of separate assemblies
Precise spring rates
Reduction of complexity and cost
http://heli-cal.com/cm/Products/Machine ... /Home.html
http://heli-cal.com/Library/PDFs/21SpringBrochure.pdf
http://www.inventables.com/technologies/machined-spring

http://www.youtube.com/user/HelicalProducts

"Machine spring sizes are limited by machining practicality. The smallest springs are about 0.100 in. (2.54 mm) in diameter,"
http://www.designworldonline.com/articl ... ings-.aspx

[Mark]

Interesting how when some fuels burn they produce carbon dioxide and water, but with hydrogen all of the products of combustion "collapse" into water. In a howler tube, snorkeler, or even a jam jar imagine how much of a vacuum and feedback you could pull using hydrogen if you could cool the water vapor quickly. Maybe fuels with a higher hydrogen component/ratio over carbon would show some difference too? I remember my howler tube attempt using glowing charcoal, how it didn't work. There has to be some sort of heat gradient or contrast going on to create a tone. There's a lot to learn about sound.
"It appears to me probable that the sound produced by the air which rushes into the vacuum is more intense than that which results from an expansive force. The dreadful noise occasioned by the detonation of bubbles of hydrogen gas and oxygen is well known, and yet the lightest objects which surround the vessel are not even agitated by it ; whence we may conclude that this phænomenon is produced by the sudden vacuum resulting from the destruction of the gas."
Memoir on tubes rendered harmonious by hydrogen gas
http://www-chaos.engr.utk.edu/hst/delar ... 14-iv.html

Related tidbits
http://www.youtube.com/watch?v=FjYB8hgkvOU
http://www.youtube.com/watch?v=-x-z3IAD3g8&NR=1

Placing a little water in the bulb of a thermometer ...
http://books.google.com/books?id=hBsUAA ... er&f=false

[Mark]

"Student Ivan Rodriguez used a different approach in building an acoustic device to convert heat to electricity. Instead of a cylinder, he built a resonator from a quarter-inch-diameter hollow steel tube bent to form a ring about 1.3 inches across."
A Sound Way To Turn Heat Into Electricity
http://www.sciencedaily.com/releases/20 ... 225026.htm

[Mark]

The destructive power of space junk
http://www.guardian.co.uk/science/video ... ace-agency

[Mark]

A few more tidbits on buzz/spark coils. This first tidbit from the year 1906.

"Any amateur who has experimented with spring metal or even whalebone, understands that with a certain thickness and width of spring metal, the longer the piece in vibration the slower its speed and vice versa, the shorter the piece the faster it vibrates."
http://chestofbooks.com/crafts/popular- ... Coils.html


"In order to reduce
the sparking between
the contact points of
the vibrator coil and
to quickly collapse the magnetic field, a condenser
is used in the vibrator coil."
http://www.funprojects.com/pdf/The%20Mo ... rt%201.pdf

[Mark]

Last clip more zippy than you might anticipate
Assorted tests.m4v
http://www.youtube.com/watch?v=O7Cceo43MbI

[Mike Everman]

Yeah, he's gotten that sucker to fire up into pulsejet mode! very cool! I've not seen that in other than your Logan. tremendous!

[Mark]

I wonder what the average frequency is?

[PyroJoe]

For the Thermo Jar:
Spear software is showing a band at about 350, and a wider band up near 530.

Another software is picking up on 538 the last part of the run.

[Mark]

I wonder if you had a very tiny jam jar if you could glue a toothbrush bristle to the bottom and have it skitter forward from the vibration of the combustion process. It's neat how toothbrush bristles can be used to propel/march resonating objects.

Bristlebots seem to have quite the following.
http://www.youtube.com/watch?v=rUSTXUis_ys#t=2m20s
http://www.youtube.com/watch?v=d48tv2BsuhQ
http://www.youtube.com/watch?v=AhGYXwno ... re=related

"You can't find a project that is simpler or more fun to build and play with than a Bristle Bot."
http://www.youtube.com/watch?v=dmsAAt5q ... re=related

http://www.youtube.com/watch?v=DALGv_fZ ... re=related

[PyroJoe]

Maybe a plastic jar on its side, applying the oil can effect plus generated thrust. That would be zippy. A pulse jet bristle bot.

[Mark]

One more doing an obstacle course. I liked the larger size.
http://www.youtube.com/watch?v=CsLmwD2G ... re=related

[Mike Everman]

One more doing an obstacle course. I liked the larger size.
http://www.youtube.com/watch?v=CsLmwD2G ... re=related

I love these! Good find. It's very timely for a project I'm on. I had just recently theorized this, and there it is. I called it a "skitter bearing". Bristlebots are cool.

[Mark]

Rotation During Compression - Helical Machined Springs Demonstration
http://www.youtube.com/watch?v=71027TUMMe8