The forums are retiring and are now closed for new topics and comments. The existing content will remain online and accessible through 2020 to provide everyone the opportunity to save any relevant information. In the spring of 2021, these Community forums will be taken offline.

# Search for theory in Topics

Which things I need to know to study relativity theory? And any good book to study it?

### Another theory...

I was wondering if this is doable, or even practical for that matter. So I read up on lasers and from what I can tell it is a form of light in which the wave frequencies are perfectly aligned. So I was wondering if you aligned UV light wave frequencies, would you get a laser that would burn stuff, and not to sound morbid, but in high quantaties, kill people. (Only for the sheer exitement of figuring something out am I posting this. I do not in any way want to kill someone.)

Topic by vroom...vroom...    |  last reply

### My theory...

So here is my theory. If you did all the math, (which I did),  and made a syrup of the exact viscosity. Would that syrup flow like water underwater just like water flows in air. Here is a diagram with all the math there for you.   I created a simple ratio... the number at the bottom right is my perfect syrup viscosity.

Topic by vroom...vroom...    |  last reply

### Checking Theories

In this topic, place your theories of some chemistry experiments in the comments section, starting with this one. To start with, Fe + 2H2O --> FeO2 + 2H...Place iron fillings to fill 1/3 of a water bottle. Fill the rest with water, and place a balloon on top. Wait X days/weeks/months. The water reacts with the iron to extract the oxygen from the water, leaving only hydrogen, and rust in the products. In the reactants, the hydrogen was bonded to the oxygen.Will someone tell me if this works? The energy that bonds this is the potential energy in the water.

Topic by PKTraceur    |  last reply

### My "theory"!!!!!!!!!!!

"The world was created in 7 days" Is one "day" for us, one day for God? 1 day for God could be 1 billion years or something.

Topic by assasin    |  last reply

### Scientific Theory

I am working on a scientific theory and I need a little help. I have 2 car batteries in series to create 24v need to power an electric motor. The motor is 14.5 amps and I need a way to control the amperage from the car batteries to the motor. Any help would be greatly appreciated.

Topic by Ice Dragon    |  last reply

### "Growing Earth" theory ...

Hi.I was wasting some time on Google Video, and I found this one.This man believe Earth (and others planets) are expanding ...According to Wikipedia, this theory is not new, and is serious. After all, if the Sun (and stars) grows, why not the "core" of planets too ?

### Unified field theory?

I was windering if someone could tell me how to add gravity to the Unified field theory? thanks

Question by RelyNupon    |  last reply

### Music Theory 101

Hello, i got an idea of making a series of detailed, yet easy to understand instructables on music theory. i mean music theory, and i mean things you would learn in college level class. i preety much dedicated most of my life to music theory, piano, cello, and listening, as well as analyzing written music. i have also had great teachers that thought me a lot of things about music and life, and i would only feel like the greatest asshole alive if i didnt share them. one thing that is special to music theory, and only to music theory, is that it is a field of study that originated from art, not vice versa. those instructibles would cover preety much everything involved with music, including the mathematics and physics that go with it! history will be included too! the reason why i'm posting it here, is to see how many people are interested, who would want to help out, and to look for reccomendations and requests. my resume: 5 years piano 4 years cello 9 years music theory perfect pitch played in 4 different orchestras considering starting doing a chamber music program, orchestras are getting boring now :D im part of the Tri-M music honor society and i volunteer sometimes. PLEASE REPLY WITH WHAT YOU THINK ABOUT THIS PROJECT :D music theory

Topic by macplo

### theory of water rocket?

Question by ainmiey    |  last reply

### Solar oven theory

When looking at various solar oven on instructables, they almost all use refective coating of some sort on the inside. That to me makes sense for the concentrators/parabolic/funnel ovens, etc. I am just wondering if the regular box ovens if it really makes as much difference or if the heating factor there is more so just the still air in the box being heated and not able to escape. I want to start making solar ovens to get an idea of how they work. I have a square piece of 1/4 inch glass, probably 4 ft by 3 ft. I thought about just digging a cubic hole in the ground and laying the glass over top.

### Big Bang "theory" Dbunked!

Topic by slasinski    |  last reply

### How do resistors react in an LED-Array? Answered

Hey guys. I've been reading myself through a lot of articles on websites about how resistors and LED's work, but what I still don't understand is why, when calculating the required resistors for an LED-Array, this website ( http://led.linear1.org/led.wiz ) takes maximum 4 LED's for each resistor at 9V and a diode forward voltage of 2.0 - is it to prevent it become unstable or something like that? And frankly, I think that I miss understand resistors, although I've read a lot of articles about it. So, what I think resistors do is this: Since resistors are used in a simple 1-LED-circuits that has more voltage than the diode forward voltage, it simply lowers the voltage to  the desired forward voltage ( 2.0 for a Red-LED as far as I remember ) - so my point is, when it always is lowered, why would you need more resistors when the voltage is lowered from the first LED on? Perhaps I am very bad at explaining my logical problem here, but I hope that someone actually understands something out of this mess. xS

Question by Zrodo    |  last reply

### New Theory For A Pump Action Gun

The black is the gun body, the red is the ramrod, the yellow is the pump, the green are the wheels, the blue could be either string or fishing line. Theoreticly i think that this gun can hold as much power as you can pump if you use high quality fishing line and you have built a strong gun body. I think that this could be a very powerful shotgun if built right. i myself have tried to do this many times through but have never sucseded. I would like to see someone give a shot at this one. I looked around extinsivly and could find no gun like this. I give a thousand congrates to whoever sucsedes in building this. Also if someone does happen to build it I would like partial credit and instructions. I would like to thank all of you for taking you time to read this through.

Topic by TheAwesomestDude    |  last reply

### assassins creed hidden blade theory

Can someone please send me designs for the assassins creed hidden blade i want a real design not a paper cutout or a link to a real design

Topic by mr.militarymaster    |  last reply

### &quot;Kiteman&quot; proves theory of Reverse Evolution!!!!!

Http://www.dailymail.co.uk/news/article-1210029/Humiliation-science-teachers-Funky-Chicken-dance-class-highlights-YouTube-threat.htmlOk, my mistake. With the headlines, and the (initially) grainy photos, I thought this was Kiteman- Demonstrating the FACT that intelligent beings can "de-volve" into funky chickens.

Topic by skunkbait    |  last reply

### My Theory for How Gravity Works

So I've never really found out how gravity actually works, why it happens. But a few days ago I had a epiphany. I don't know if I spelled that right. So everything is at least a little bit magnetic, even stuff like wood, no matter how little. So all of this stuff would be attracted to all the other stuff electromagnetically, right? Even a little bit? So when you get huge amounts of this stuff (I'm thinking planets here) there is enough electromagnetic attraction to pull it together, and voila! We have gravity! Plus when you have planets, there's tons of stuff like iron and other metals and metaloids, that could be very strong, magnetically. So if I'm wrong (which I probably am), can someone explain how gravity actually works to me? I'm constantly thinking about stuff like this, I get theories like this every once in a while, many of them right. But not this complicated, more stuff like figuring out how air pressure and vacuums work, but basic principle stuff.

Topic by Aeshir    |  last reply

### will this theory work for an assassins creed hidden blade? Answered

i built this theory but i did not try will it work? note : the circles are springs , strong ones note : the back end's reach = the long of the blade gets out + the tall of half your arm

Question by top.boy    |  last reply

### What is the definition of "matter" according to the string theory? Answered

Hello!  I have recently studied about the string theory. Now what I have understood about it so far is that very small particles like the one's that make up neutrons and protons are actually made up of "strings" that vibrate in 10 dimensions at particular frequencies which determine the nature of the particles that they form. I also came to know that "strings" themselves are weird distortions of space-time.   Now I don't know if all that information is correct or not. So my question is that according to it, it would mean that matter itself is a distortion of space-time, is this true?

Question by Wisaam    |  last reply

### Is there really a theory behind the hojo motor scam? Answered

I ran into it on line.  More truthfully, it ran into me.  I've never heard of it.  I do know it's a scam, you can't spend \$100.00 at the hardware store and build a device that supplies 120 volts at 2oo amps to power a house.  The whole thing did pique my curiosity, just like a gasifier or hovercraft or flying lawnmower would.  The problem is that if you try to find just information on what the thing is all you get is page after page after page of scam sites or people trying to sell plans for some mythical device. The only thing I've been able to ferret out is that it's some kind of perpetual motion device that will power my whole neighborhood if I spend 9 hours building it.  I like to think none of my fellow humans are silly enough to believe that. Anyway, without trying to tell me you have one powering your house and an orphanage out of kindness or trying to sell me plans please explain the theory behind it.  Sorry if I sound grumpy, I've been battling scam sites trying to look legitimate for the last hour.

Question by AngryGuy70    |  last reply

### How does radio really work?

I'm studying to take the exam for a technician class ham radio license, and have been reading up for it.  However, the book just gives practice, not theory.  For example, it says that radio energy is carried down a coaxial, window, etc. cable between the two conductors, but it doesn't say how this actually happens or works.  I know what radio does, but I'm a little lost when it comes to theory regarding its transmission, being carried in cables, filtering, SWR, etc.  Answers are appreciated.  Thanks!

### Earth Ground?

Well, it seems about time to add to my list of electrical theory questions with answers far too broad for one question, so:                          I understand that the Earth can act as a giant capacitor, conductor, etc.  What I don't understand is why.  For instance, why would ac power from the hot wire dissipate into the ground?  (and, for that matter, will power from the neutral wire not do so?  If so, why?)

### String Theory,..this is not detailed, but what do you think?

Here is a short video (not embeddable, sorry) on the Higgs-Boson and string theory by Dr. Michio Kaku.  Comments?

Topic by Goodhart    |  last reply

### need help with ir object detecor (reflect theory)?

Hi i'm working on a small project using iri want to make an object detector for detecting people who stand in front of a door i don't want to use laser or ir beam cut theory i want to use reflecting theory so that the sender and reciver be in the same side just as supermarkets doors i have searched for many circuits but they all use cut theory this site is my local store that have parts in my country http://www.ram.com.eg

Question by aessam1    |  last reply

### Basic DC (direct current) theory and practice for newbies

Hey everyone, as you may have guessed - i'm a newbie to DC theory! Backstory: after graduating i said 'forget it' to a proper job and moved to Australia to travel. i bought a converted camper van that has an auxillary battery for (whatever), and it looks like it runs off 12 volt dc! the Question: how does DC power work, for me and all those newbies out there putting along on the other side of the planet! -cheers, adrian www.bigquestionmarks.blogspot.com

### Why did the duck go up? Any theories?

http://www.youtube.com/watch?v=-x-z3IAD3g8&feature;=related Skip ahead to 4:57. What he refers to as string appears to be an elastic material. He pulls up and it goes up. He pulls down and it goes up. The video is supposed to be about electrostatic toys.

Question by Vorenus    |  last reply

### 4 Reasons why we believe in Conspiracy theories

Did NASA really land on the moon?Did the government cover-up involvement in the Sept. 11, 2001 terrorist attacks?Is Elvis still alive and kicking? What about Michael Jackson?Was John F. Kennedy assassinated at the hands of multiple shooters?Do the Freemasons control the United States?A small but fervent group of people believe there was more than included in historical record about the aforementioned events. Conspiracies, they call them. And every generation has its own.Some of them turn about to be true, after all: Pearl Harbor was a Japanese conspiracy and NixonÃ¢â¬â¢s Watergate break-in was a coverup.But with so few that turn out to be true, why do people believe in conspiracies?HERE is the link to the Rest of the story.And one final note:so, NOW we know who was on the grassy knoll and shot JFK LOL It was JFK himself !!!

Topic by Goodhart    |  last reply

### Is it possible to draw energy from an ion chamber?

On a purely theoretical basis, would it be possible to harness a small sample of radioactive material and an ion chamber to produce a small trickle of electricity? I'm not sure what the practical use of a device would be, and I'm well aware of the risks and dangers involved; I'm asking to satisfy my own curiosity.

Question by jlensher    |  last reply

### would this work for a homemade generator?... like getting a dc motor and turning it in reverse ?

Instead of spinning the moro by connecting it to a battery spin it on the spindle that turns? would it work

Question by sharlston    |  last reply

### Tesla's "Earthquake" machine - revisited!

Topic by Downunder35m    |  last reply

### Theory, execution and actual construction of a 'Bullet-Shot Location' like system Answered

How could it be done? I have revised a version using only two microphones that once one of the microphones 'hear'  the sound, a timer will start and will stop once the next microphone 'hears' it.  This would essentially enable you to draw a line straight down the middle of the gun. It would also allow for tracking the location in real-time. How could you physically build it for a cheap set-up. I'll upload a couple of diagrams some time.

Question by Lance Mt.    |  last reply

### if we had two moons how would that in theory effect earth? Answered

Gravitational differences, water, magnetic poles anything?

Question by ismael01    |  last reply

### How do I determine the size of the image needed to reflect onto a cylinder (see Q for better description)? Answered

I plan to take a large disc shaped screen and then reflect that image onto a cylinder to create a holographic effect. Right now this is just a concept but I am wondering if this is plausible and what size the disk would need to be to create an image to cover the cylinder. If a formula could be provided that would be best or just a general explanation of how to find a formula.

Question by TheTechGuy99    |  last reply

### Why can a function satisfying same boundary conditions as functions Un(x) of a complete set be expanded as Î£CnUn(x)?

Question by Xellers    |  last reply

### How to measure open loop H(s)? Answered

When designing constant current linear dummy loads, and when I was (attempting) to design a really nice linear power supply with op amps and pass transistors, I consistently run into the devil of the circuits that incorporate feedback. INSTABILITY! Especially if I use fast op amps, or MOSFETs, etc. My understanding as to why this happens is because I still have some positive gain at the point at the frequencies where signal the total loop has that dreaded -180 degree phase (gain margin) and then where the gain is unity and phase is at -180, again allowing that frequency component to be successively amplified (or never attenuated) as that wave whirls around the loop. However, with op amp circuits, how am I supposed to get an accurate open loop measurement, when the DC gain is so stupidly high the input to an op amp is essentially a comparator? http://www.ti.com/lit/an/snva364a/snva364a.pdf This article suggests whacking in a 20 ohm resistor and injecting a signal into it, and measuring the voltage on either side of it (?) How is this supposed to work? Is there a better method in something like LTspice?

Question by -max-    |  last reply

### Relativity and why E can't really equal m²

Topic by Downunder35m    |  last reply

### Why "Vortex" for Vortex math and devices?

Topic by Downunder35m

### Which is more likely to work and which is more based on fact, the modified alcubeirre warp theory or the hiem hyperdrive Answered

Which is more likely to work, the alcubierre drive which allows for superluminal travel using a Jupiter's mass of energy or the superconducting gravito-photon effect that powers the theoretical hiem theory hyperdrive?

Question by amelius    |  last reply

### Old Phone That Can Play Games? Ideas...

Hi guys, so I was recently talking with my friend Omar about random stuff, and (like always) our conversation somehow got really off track and we ventured into the history of old phones (Nokia 3310...breaking everything we touch since 2000). We somehow got to thinking about how old bar style phones could be useful for the making community. My thought (which I incidentally shouted out as loud as a human can go) was this: what if we could put a really basic game onto the phone? Would it be possible with the current hardware? Maybe...and the controls are there, most phones have a D-pad with 12 keys (which could be special function keys in the game). I was thinking of games along the line of Doom, or any old FPS game...but in retrospect, that would be ambitious, and to be practical, a stick man game would probably be the minimum.  So my questions are: a) would it be possible for the hardware on the phone to be wiped of all software and would it be good enough to support the code. b) is it even possible to reprogram the phone, or even get some sort of bootloader onto the device? Probably not. And if not, is there any other way to put a game or any file onto the phone's hardware... I guess that's it. In general, would it be possible, and if yes, could anybody give me a few starters so I could try to do it? Thanks, Ivan

Topic by IvanT3    |  last reply

### Tesla's earthquake machine - was it just a practical joke?

Topic by Downunder35m    |  last reply

### Xylobands

Anyone  got any theories on how the xylobands work? Especially at the £3 a piece mark? www.youtube.com/watch?v=zxYjRx9fJgY

### What does it take to become a scientist and an astronomer ? Answered

Question by Gopal Dey    |  last reply

### Is it possible to create a magnetic difference engine using stirling theory? Instead of hot and cold can strong and weak Answered

I just got finished building a stirling engine using plans from instructables author: thecheatscalc published dec 17 2007. The stirling engine is a heat difference engine. Is it possible to create a magnetic difference engine using stirling theory? I was thinking instead of hot and cold north and south or strong and weak..?

Question by bazalaz    |  last reply

### does anyone know how to make a mobile virtual presence device like the one in the big bang theory?

Question by commander spock    |  last reply

### In theory, can you hook a turbocharger to the end of another turbo to make the 2nd turbocharger spin at a faster rate?

I need to know if you can hook a turbo to the output of another turbo so produce a faster rate and air flow, not for car so dont worry im not going to blow up my engine. Also wondering a couple other things car parts related while I am at it, how much force does it take to spin an alternator when its "on". i know that when the car is not on it free spins but once it is and does not have belt hooked to it it is hard if not impossible to turn by hand. thanks for the help.

Question by jobergy    |  last reply

### Taylor Couette

Does anyone know how to make the Taylor-Couette apparatus (as illustrated here) http://www.youtube.com/watch?v=pKrnM9uNXRw ?

Topic by piimapoika    |  last reply

### Nova's Elegant Universe

Nova's Elegant Universe is a very well made scientific documentary about string theory. If any of you have been interested in The Fabric of the Cosmos by Brian Greene but don't have a chance to sit down and read something. This is for you.String theory is trying to unify our understanding of everything through one equation, if you think that is interesting then: Click here to watch the entire series // More Brian Green at TED here \\

Topic by lamedust    |  last reply

### Can the human body be used as a battery?

My son and I are working on his science fair project which is to light a light bulb using a piece of copper pipe, a piece of galvanized pipe, and two wires with alligator clips to connect the light bulb.  The theory is that holding the two pipes in ones hands, the  body will create enough current to light the bulb.  We have not had any success yet.  Even wetting our hands had no noticeable affect.  Any ideas?  Is this a plausible theory?

Question by speedway1839    |  last reply

### Air Compressor/Vacuum Pump

I have a theory: You have your supply of compressed air. You connect that by hose to one branch of a y-connector. The other branch is connected to a hose that goes into some sort of fluid that you want to move from one vessel to another. The trunk of the y is your exhaust (in theory). So now I give, say, 15 psi out of my air supply and that shoud drag my fluid out of its vessel through the y connector to the destination of my choosing. Would that work?

Topic by flagrantfouler    |  last reply

### This is what happens when you're too lazy to buy a real webcam:

Not practical at all and in theory this was more expensive than buying a real webcam but it does work: