To All Budding "Anti-Gravity" Scientists...

[RainmanTime]

To All Budding \"Anti-Gravity\" Scientists...

:D

In weeding out hoaxy/cranky "anti-gravity" scams from real science in physical dynamics, one can hone their skills by being able to look at a physical situation and express it in equations. What follows is a story that examines this from an "anti-gravity" observation I just made in my kitchen. The challenge is to see if you can take this observation and reduce it to a set of equations from KNOWN SCIENCE to see if you can describe the physical action which seems to lead to an anti-gravity effect:

I was just making a batch of my "world famous"(?) Honey-hot teriyaki chicken wings (TM Ray Hudson 2008). When I get to the phase where the wings are in the oven and I am basting them, I use a long, sturdy baster to suck up the teriyaki-honey "juice" from the pan and dribble it over the wings every 15 minutes. After I am done I return the baster to a tall, thin glass on top of the counter because the baster still has some of the VERY hot liquid trapped inside it, and becomes very drippy. When I return the baster to stand, vertically, in the glass I give one big squeeze to get all the remaining "hot goop" out of the baster. But then....I see it... I see "anti-gravity" at work before my very eyes!! /ttiforum/images/graemlins/ooo.gif /ttiforum/images/graemlins/loveit.gif In my own little kitchen, no less!

Within 30 seconds, ALL of the "excess" honey-teriyaki juice in the glass is no longer in the glass... or at least it is gone from the bottom of the glass! Over the period of those 30 seconds I watched the hot juice propel itself UPWARDS (by what MUST be the sheer force of ANTI-GRAVITY!)

into the tip of the baster tube! /ttiforum/images/graemlins/tongue.gif And let me tell you, these wings are the tastiest honey-teriyaki wings ever...EVER!

OK....so maybe it is NOT really anti-gravity! /ttiforum/images/graemlins/smile.gif But what is it? How would we begin to derive equations that might describe what is going on? It is easy enough to just say "oh, it must have something to do with heat because of the temperature of the hot liquid..." and leave it at that. But it is NOT heat and/or temperature ALONE that is responsible for this effect. For one thing, pressure is involved. For another thing gravity (AH HA! SEE! IT IS ANTI-GRAVITY)...no, I mean the nominal gravitation field of the earth!! Yes, THAT is involved in these equations too.

Who wants to take a stab at how we would begin to formulate the problem? Any volunteers?

RMT

 

[Einstein]

Re: To All Budding \"Anti-Gravity\" Scientists...

Hi Ray

The liquid moves up the baster tube because the gas inside the baster tube is cooling down. The thermal conductivity of the baster tube has two parts. The tube itself, and the elastic bulb. Air temperature and pressure inside and outside the baster tube come into play. The weight of the fluid as it moves up the baster tube comes into play, which will effect the air pressure in the baster tube. Also as the fluid moves up the baster tube, the radiative surface area for the gas to dissipate its heat inside the baster tube is decreasing. Lets just throw in a cold front moving through for good measure. That would mean the outside air pressure and temperature are changing as well. The thing that bothers me is determining the thermal conductivity of the baster tube. Without having some basic data to access to determine that rate, it may have to be determined by trial and error. The rate doesn't seem to be constant when I run through the visualization in my head. Did I leave anything out?

 

[s19n]

Re: To All Budding \"Anti-Gravity\" Scientists...

You left some detail out of the description. You should post a video (with narration!) /ttiforum/images/graemlins/smile.gif

 

[RainmanTime]

Re: To All Budding \"Anti-Gravity\" Scientists...

Hi Einstein,

Did I leave anything out?

Perhaps not, but... as you should know by now, I am asking who might have a foundational approach for where to begin. I know where to begin, but I was going to see if someone else would suggest it as a starting point. You almost hit upon it:

Air temperature and pressure inside and outside the baster tube come into play. (snip)
That would mean the outside air pressure and temperature are changing as well.

The foundation we should (and must) begin with is a reasonable steady-state model of the atmosphere. Why would you assume the pressure and temperature outside are changing as well? It may very well be, but given the size of the external atmosphere, it could certainly be considered (as we usually do in such problems) as an "infinite reservoir at equilibrium".

The principal we should begin with is the hydrostatic principle, which describes how pressure is distributed in any fluid (a fluid can be a gas OR a liquid). This is a fairly simple derivation that is in any freshman year aerospace engineering book. It begins by drawing a single "chunk" of air and identifying and labeling the forces acting upon it in the vertical direction. (I will add some diagrams to this explanation when I get home).

Ignoring the setup and math gymnastics (for now..if someone wants to see it, let me know), we can arrive at an equation that the following for any vertical column of fluid:

P(x+1) = Px + rho*g*d(x+1) where:

Px = Fluid pressure at the "top" of the column of fluid (i.e. a "zero reference point") in units of pounds per square foot.
rho = Density of the subject fluid (in this case, air) in units of slugs per cubic foot.
g = Gravitational constant (assumed constant, reasonable assumption for small altitude changes) in units of feet per second squared (also, with a value of 32.174 feet/sec^2).
d(x+1) = The vertical distance from point "x" to point "X+1" in units of feet.

One way to determine if this is an acceptable place to start is: Does it accurately model something we can observe in nature? The answer is, yes it does. When you jump into a pool and dive from the surface downward, the pressure increases proportionally to the depth you dive. The "rho*g*d(x+1)" defines that proportional relationship. This also tells us something about the pressure outside/around the baster: It may not be changing as a function of TIME, but it is certainly changing as a function of distance (up the shaft of the baster).

This may be important, since the above equation will tell us that the pressure at the very bottom of the baster is HIGHER than the external pressure outside the baster up around the handle.

RMT

 

[Einstein]

Re: To All Budding \"Anti-Gravity\" Scientists...

The foundation we should (and must) begin with is a reasonable steady-state model of the atmosphere. Why would you assume the pressure and temperature outside are changing as well? It may very well be, but given the size of the external atmosphere, it could certainly be considered (as we usually do in such problems) as an "infinite reservoir at equilibrium".

I suggested a cold front was moving through at the time of the experiment. So air temperature and pressure would be changing externally. Probably at a rapid enough rate that you would want to include it as a variable in the final equation. The reason I chose this was because so often everyone just wants to choose off the shelf equations to describe what's going on. But quite often it isn't an accurate description. By including an extra variable, you are now forced to modify the existing equations to suit your needs. This is something that was not taught to me in school. So when faced with a problem like that, I usually just try an see if I can use something I know to help bridge the gap. Algebra was one of my favorite math classes, as was Calculus. But I still use algebra quite frequently to help me solve lots of problems. So I would apply that knowledge to help modify an off the shelf equation.

I'm still not quite clear on what aspect of the fluid moving up the baster tube that you want to investigate. Mainly because I thought of some additional phenomena that was going on. Initially when you first put the baster tube into the container on the counter, the air pressure inside the tube is equal to the outside air pressure. Just briefly of course. But in that brief instant the air in the baster tube is at a much higher temperature than the surrounding air. That hot air is enclosed within the baster tube. That would suggest that there would be some buoyancy effect. The baster tube and container should weigh less in that brief instant than towards the end when thermal equalibrium occurs. Given a specific density and volume for the hot air might actually show how much bouyancy potential is available.

 

[Darby]

Re: To All Budding \"Anti-Gravity\" Scientists...

Ray,

Hmmm...I'll have to think this one over for a while. But I'll start here with some observations of your set-up:

You have a very hot liquid that consists of sugar, liquified chicken fat, salt water and soy. That's a nice mixture similar to what might be in a petro cracking tower.

You sucked the hot liquid into the baster and then put it into the glass. The liquid leaked out into the glass. The temperature of the glass was likely at room ambient temperature.

The liquid started to cool. The temperature at the glass-liquid bound shortly approached thermal equilibrium. At the same time the portion of the baster that was not immersed in the liquid approached thermal equilibrium with the air.

As the liquid cooled the chicken greese should have rose to the top. It is a fairly good insulator. The sugar should have gone to the bottom of the glass. It's also a good insulator (the cracking tower is working now, BTW

). The salt water-soy liquid should have been between the two insulating layers. There was a temperature gradient (some sort of del function) for the liquid. It was cooling more quickly at the glass-liquid bound than than it was at either the sugar-water or grease-water bounds. The salt water in the middle was fairly well insulated. The Brownian motion of the molecules in this particular fluid would be very different than had the liquid been pure distilled hot water, for instance.

The baster, though it was at equilibrium should be reheated by the salt water. That re-expanded the tube thus reducing the air pressure inside the baster.

If the tube expanded sufficiently the pressure differential should allow the liquid to rise in the tube.

 

[reactor1967]

Re: To All Budding \"Anti-Gravity\" Scientists...

E = - rho * L * k * ustar * (q2-q1) / ln(z2/z1)

where E is evaporation, rho is air density, L is the latent heat of
vaporization, k is von Karman's constant, ustar is the friction velocity,
(q2-q1) is the specific humidity difference between the air and near
the water surface, ln is the natural log, z2 is the height of the
dew point temperature measurement, and z1 is a height near the
water surface. There you go, Thanks, Reactor

 

[reactor1967]

Re: To All Budding \"Anti-Gravity\" Scientists...

I got one for you. Anti-gravity I thought was suppose to be the reverse of gravity which is really gravity. So, we have the moon and the earth. The moon's gravity is responsible for causing tides in the oceans on earth. Everyone has heard of high tide or low tide. So, here is my question to you. Is the gravity of the moon pulling on the earths oceans considered anti-gravity? What do you think? Reactor

 

[Darby]

Re: To All Budding \"Anti-Gravity\" Scientists...

Reactor,

My friend, two problems here. First the issue here isn't one evaporation rates. Second, we usually give credit to the original author when we quote them verbatim.

Evaporation Rates -

BTW: I believe that Ray might be "somewhat" familiar with the late AE pioneer Dr. T. von Karman considering that Ray is an aeronautical engineer and the bulk of von Karman's fluid dynamics work was in the related field of aerodynamics & sub, trans and super sonic flight theory. . /ttiforum/images/graemlins/smile.gif

 

[reactor1967]

Re: To All Budding \"Anti-Gravity\" Scientists...

ok, I read the question too fast. He is sucking up the juice not letting it evaporate. Yes, I went and looked up the equation for vaporation. I really don,t call that plagiarism as you seem to be calling it now because I simply gave the description of the variables nothing else. And, to well known and documented information. Not to an original work. So, this is not plagiarism. You and Ray call me out when I don,t describe my variables so I was just simply granting you and Rays request to describe my variables. Im sure you and Ray look up equations too. Anyone who works in the field of math or science do it from time to time and when they do they also have to look for a description of the variables or figure it out on their own if they don,t already know it. Darby, you really need to study up on the defination of plagiarism before you start accusing others of it. The description of the variables to that equation do not meet the defination for plagiarism at all in any way what so ever because the discription is not an orginal work. If I posted a description to E = MC^2 that everyone commonly agrees with that is not plagiarism because that is public knowledge not an orginal work. But now to move on to my next question which was why I was really here. Lets see if anyone is can answer it. Is the moons gradational pull on the earth considered anti-gravity? Are we still talking science here? What do you think?

P.S.

Plagiarism is the practice of claiming or implying original authorship of (or incorporating material from) someone else's written or creative work, in whole or in part, into one's own without adequate acknowledgement.

Nothing in the description of math variables from well known and documented information is not "orginal work" therefore can not be considered plagiarism. Sorry to burst your bubble.
Thanks, Reactor

 

[reactor1967]

Re: To All Budding \"Anti-Gravity\" Scientists...

The process you are describing after being corrected from my earlier post is called "Vacuum levitation". You are squeezing all the air out of the tube then using the negative air pressure to suck the juice up into the tube where it is suspended or levitated by the difference of air pressure from the outside and inside of the tube. Given the time I could probably look the equations and post it if no one had a problem with it. Thaks, Reactor.

 

[RainmanTime]

Re: To All Budding \"Anti-Gravity\" Scientists...

The process you are describing after being corrected from my earlier post is called "Vacuum levitation". You are squeezing all the air out of the tube then using the negative air pressure to suck the juice up into the tube where it is suspended or levitated by the difference of air pressure from the outside and inside of the tube.

Incorrect. When I squeeze the juice out of the tube, I then release the bulb and allow the pressure to equalize before I put the tip of the baster in the glass. It is then that the juice in the bottom of the glass bubbles up into the bulb again.

And no, the tidal action of the moon on the ocean is not considered anti-gravity. It is merely the gravity of the moon acting in the opposite direction of the gravity of the earth on the ocean's water. The term "anti-gravity" is generally used to refer to some force that nullifies (counters) the effect of a local gravitational field on some body that is subject to that gravitational field.

RMT

 

[reactor1967]

Re: To All Budding \"Anti-Gravity\" Scientists...

Thank you for the reply and for the correction. I need slow down. Ok, here I go again. The hot liquid heats the hot air. As I understand it the hot air rises because the air is less dense. The rising air creates a sucktion that "vacuum levitates" the hot liquid. My untested theory now is if we cool this tube down the liquid will come back out. Forgive me but I will hold off trying to prove it mathematically. This is what I have. Thanks for your time. Reactor