Mystery of the CO2 Balloons!

Filled some balloons w  co2  from dry ice in a soda bottle.   As expected, they act like a lens, a magnifier of sound. No mystery there. Just as a dense glass refracts light, the denser gas refracts sound. The mystery is why balloons filled with co2  leak down faster than identical balloons filled by mouth. Yes, there is some co2 in my exhaled breath, but it is mostly  n2,  and  o2.  I would hav expected the n2 and o2 to leak out more quickly, being smaller molecules. So whatzup wit dat?

Topic by Toga_Dan 4 years ago  |  last reply 4 years ago


What is the smallest helium balloon that could lift an average human?

I am trying to figure out a way to lighten a load with helium balloons. I am looking for a way to make them portable too, i.e. to be carried in a backpack. Is there a more readily available gas that will do the same job without blowing up, or is helium the current best bet?

Question by jemb29 7 years ago  |  last reply 7 years ago


can compressed gas leak through a metal tank? Answered

So the other day i was talking with my friend and  he told me that gas can leak out of a metal tank.  he said gas can leak out of scuba tank going through the metal just like it goes through a latex balloon.  so i wanna know is this true?  could gas leak out (given enough time) through a 12 gram CO2 tank used for airsoft for instance?

Question by cdubnbird 8 years ago  |  last reply 8 years ago


question about floating things on SF6 or any other gas

Hey guys, I have this burning desire to float something on SF6. Rather than just balloons or foil boat. Right now i am thinking about dandelions seeds, dust bunnies? dead insects? is there any way for these things to float on SF6? or any other gas? In addition, if i use a balloon full of air, how long can it stay up before going back down? if i seal the fish tank up really good, can i keep it up for a good amount of time? Please let me know what you guys think! Thank you so much!

Topic by haoishao 6 years ago  |  last reply 6 years ago


Can a vacuum balloon be built with current material technologies? Answered

A balloon's bouyancy (lifting force) is a function of how much air it displaces. Today's balloons use hot air, hydrogen, helium and other lighter than air gases for lift. In 1670 Franceso de Lana, an italian monk, proposed the use of a vacuum. One major problem is how to make the structure light enough to support a vacuum without collapsing in on itself due to the outside pressure.

Question by sansoy 10 years ago  |  last reply 4 months ago


How to make a mylar balloon from a space blanket

I want to make a hydrogen balloon and am afraid rubber won't hold the gas in well enough. I was thinking I could make a balloon from a space blanket but am not sure how to connect the edges. I thought maybe I could fuse them with an Iron but am not sure. Will apreciate any help.

Question by nurdee1 7 years ago  |  last reply 6 years ago


How to produce 14,000 cubic feet of hydrogen? Answered

Okay, here is the deal. Me and a friend where thinking about filling two weather balloons( http://www.ebay.com/itm/GIANT-Weather-Balloon-Meteorological-Military-8-Dia-/330626487344?pt=LH_DefaultDomain_0&hash=item4cfadfd430) with a lifting gas, sending it up with a camera and gps-cellphone. Now, we have everything else figured out but how to get hydrogen, as it is the lightest gas. Is there any way to produce those quantities of hydrogen within a 6-36 hours? I figure I'd ask here because there are quite a few hydrogen powered vehicles here.

Question by bretta 7 years ago  |  last reply 7 months ago


Brainiac's: Cool Things in Slow Motion including exploding a balloon filled with gas

The following video shows a few things that we have seen and take for granted, only in slow motion. Some are real eye-openers...

Topic by Goodhart 11 years ago  |  last reply 8 years ago


Producing Hydrogen to Function as a Lift Gas

The short version: I want to make hydrogen to fill model airship envelopes with, because screw helium. Help me make a cheap electrolysis device that can do this in under an hour (ideally), or come up with an even better system for production. My immediate problem is that I need a high-surface electrode that won't fail in a solution of sodium hydroxide.The long version:I've devoted a fair portion of my time to contemplating airships, primarily because they're awesome. Fell out of use with the rise of much faster aircraft, and the technology its fate sealed by the extraordinarily bad rep the Hindenburg gave it. It is still far from useless, however, in that lighter-than-air systems can lay claim to flight times measured in days, and sometimes months, thanks to the fact that they literally float in the air like a boat floats in water.Their day may have come and gone, but I still want to experiment with the technology and create some model airships of my own. Helium works okay as a lifting gas, but it remains expensive and isn't going to get any cheaper in the foreseeable future. It is for this reason that I am pursuing hydrogen, in the hope that I might be able to produce a cheap lifting gas for my projects. Unfortunately for my aspirations, hydrogen is surprisingly hard to get cheaply in decent quantities. Here's what I've figured out so far.For one, it is absurdly hard to find sites that don't veer into fringe science when talking about hydrogen. HHO production, Joe cells, power your car with water...it all keeps cropping up, and not only does none of this do what I want, the concepts are often poorly documented or riddled with problems. However, I have been able to glean some information from my research. First off, one of the easiest methods (and the one I'll be pursuing the most) of hydrogen production is through electrolysis. For those of you unfamiliar with the concept, you can basically take two electrodes, stick them in water, add some electrolyte (like regular table salt), and apply a decent voltage. You'll get hydrogen gas streaming out of the negative electrode and oxygen out of the positive electrode. Fancier systems use large tanks, platinum electrodes, and a strong acid or base as the electrolyte. To increase efficiency (yeah, it's not 100% efficient), there is ongoing experimentation with high-temperature electrolysis and ongoing research into an effective electrocatalyst.Now, when I did my research, I thought "Hey! This sounds easy! I'll just set the system up like explained, and away we go!" Unfortunately, those exclamation marks were unwarranted. My first attempt showed that production is mind-numbingly slow with small electrodes. Using salt had the wonderful side-effect of producing chlorine and sodium hydroxide, a.k.a. caustic soda. It's called that for a reason, and I'm lucky I didn't run it too long or I might have a chemical burn now. Now I know. Choosing a good electrode turns out to be a problem too, as most conductors oxidize quickly or dissolve in the solution (now I know why everybody uses platinum when possible). My aluminum foil electrodes in a sodium hydroxide solution? Yeah, that didn't work AT ALL. I had better luck with steel mesh, but I recently found that it seems to fail over time too. The only thing that isn't disappointing is the container and the collection apparatus: an inverted plastic bottle with some airtight hose running off it, connected to a gas valve. If the bottle is placed such that forming gas causes the internal water level to be lower than the external container water level, the gas will be pushed through the hose (no pumping necessary!). There was one good thing I discovered, however. Apparently there was a bit of soap or something left over in the container, and I ended up forming a bit of explosive foam as well. The hydrogen foam blows up like nothing else, and the oxygen foam makes a loud pop and sends (slightly) caustic foam all over the place. Totally useless but still somewhat cool, so long as you're not fool enough to do it in large quantities.So, as of right now, I've got a good container and collection system, but my electrodes suck and production rates are so low that it'd take me hours and hours to inflate a good-sized balloon anyway. I'll be using sodium hydroxide in the future as the electrolyte, skipping the chlorine production and observing the proper safety procedures. My top priority is finding a good electrode, my next is finding a good way to increase surface area, and my last is getting a higher voltage source than the 12V power supply I had lying around. Any ideas?

Topic by Cognoscan 9 years ago  |  last reply 8 years ago


inflatable plane

I would love somebody to build a 2 seater plane that is collapsable using a telescopic carbon fibre frame and wings covered with a balloon type inflatable skin and cockpit using helium as the inflating gas it would in theory be light enoug to be powered by a microlite engine. And after that a helicopter on the same principals.

Topic by will1947 10 years ago  |  last reply 10 years ago


How do I collect the oxygen from the reaction of hydrogen peroxide and manganese dioxide?

I believe that the reaction between the black, powdery manganese dioxide found within carbon-zinc batteries, and household-variety hydrogen peroxide produces oxygen. However, it is my understanding that oxygen is heavier than air, and will therefore that collecting the gas will not be as simple a matter as seen in steven07's Instructable on producing and collecting hydrogen.Unless I'm completely wrong, and a reaction that produces oxygen will inflate the balloon. :POr, does anyone else have another way of collecting the gas?

Topic by carbon 12 years ago  |  last reply 5 years ago


what else can you float on SF6 other than foil boat and balloons? also how long will SF6 in a tank keep something afloat

I am basically trying to figure out other things to float in a tank of SF6 ( or better, heavier gas?) Right now I have dandelion seeds, hair, insects in mind. Do you think these will float?  also If i ended up using a foil boat, how long will SF6 keep this boat afloat? what if i seal up the fish tank really good, will the boat be afloat forever? Please let me know! thank you !

Question by haoishao 6 years ago  |  last reply 6 years ago


The Dangers of Disney

I was trying to find out who was currently leading the US presidential polls, when I got distracted by an item on Freedom of Information. That led me to this article. Isn't the internet wonderful?Inhaling helium to produce an amusing squeaky voice (a favourite game for children in the United States and Europe) may not be the innocuous party trick it seems, according to emergency medicine physicians at the Wesley Center for Hyperbaric Medicine in Brisbane, Australia (Annals of Emergency Medicine 2000;35:300-3).Simon Mitchell and colleagues report the case of a previously healthy 27 year old man who inhaled helium and subsequently developed a stroke with transient blindness and radio-graphic evidence of cortical infarction. However, the man had inhaled the gas direct from a pressurised canister, whereas most children who perform the trick - to imitate the voice of Mickey Mouse - inhale the gas from helium filled balloons.The patient developed rigidity and lost consciousness within moments of inhaling the helium. On arrival at the emergency room 15 minutes later, he regained consciousness but was found to have complete visual loss and evidence of cortical infarction.PubMed ArticleI still haven't found out who's leading, though...

Topic by Kiteman 10 years ago  |  last reply 9 years ago


Instamorph Build Night at Arch Reactor Hackerspace, St. Louis, Missouri

On Tuesday, April 21st we held a build night at Arch Reactor (in St. Louis, Missouri) with Instamorph. There was a very excited turnout of over 15 people being introduced to the moldable plastic product. Some members incorporated their creations into existing projects, such as a loop to hold a weather balloon safely onto the quick release pipe during the pre-launch filling in order to measure the total lift without losing any of the gas. Another member created a diffuser for a LED project that used RFID tags to cause different combinations of colored LEDs to turn on when a tag was scanned.  Others experimented with the product to discover ways they might use Instamorph in other projects in the future. The big discoveries of the night were that any unused portions or failed creations could simply be placed back into the hot water and reshaped into version 2.0 or something new entirely and that once it cools Instamorph is virtually indestructible. See the photo of a flat sheet of it being bent into a taco shape. Process: We used an electric kettle to heat up our water to the correct temperature of 140 degrees F / 60 degrees C, and then poured it into small bowls. I had initially thought that each person could start with 3 ounces of the pellets, but the measuring cup that I brought only held 2 ounces. After heating that portion up in the water, we discovered that 2 ounces was plenty for most projects being considered. The member in charge of our workshop had asked those who did not have an idea for the Instamorph to consider making a hanger to hold individual shop safety glasses. He molded a piece into a design for that. Later it was discovered that the hearing protection holder dome in the shop was exactly the size to hold shop glasses. Attempts may be made later to fashion a "nosepiece" and "earpieces" from Instamorph and attach them to the dome to hold several pair of safety glasses on it instead of on the wall. It was also discussed to place a safety glasses holder at various stations throughout the shop to make them more accessible for users in the shop, and thus more likely to be worn.  Problems encountered:  The bowls that I had brought were plastic, so if the heated pellets were pressed into the bowl hard enough they would stick a little, but could be pushed off with just a little effort. In retrospect, I would use glass bowls the next time.  I would also consider using a crock pot to keep the water at a near constant temperature for any personal projects, but the electric kettle and bowls worked well for the build night. We also had an issue with the warmed Instamorph sticking to an acrylic roller and a plastic mold meant for cake decorating. It worked fine if the Instamorph had been allowed to cool while flattening it out by hand, then rolled. However, when it was removed from the water and immediately rolled, it cooled quickly and adhered to both the acrylic roller and the plastic mold. Much scraping, reheating, and elbow grease were applied in order to remove the Instamorph from those tools. Tools made from other materials might work better for this process. 

Topic by GeekTinker 4 years ago  |  last reply 3 years ago


Homes Protected from Raging Forest Fires

Every year we hear about countless homes being destroyed by forest fires. Unfortunately, the public isn’t aware that our current level of technology can readily address this problem. I have been examining a concept that has intrigued me over the past decade and which I call a “fire shield”. This shield functions by completely enveloping a private home and protecting it against encroaching forest fires. We’re talking about protection against a blazing fire storm generating high speed winds and flames in excess of 100 MPH. The shield would be a flexible structure that easily inflates like a balloon (needing perhaps three people for a day to erect) and forms a protective hemispherical, shell-like dome over the home (Fig-1). The structure would be impervious to penetration by high speed flames and their intense radiant heat, thereby keeping the enveloped home safe, cooled and protected. Each home would require a pre-fitted, customized buildup of a number of pre-built modular, balloon-like segments. They are manufactured and then assembled over the house only once, to get a customized tailored fit, then taken down and stored, and thereafter are ready to be deployed within a day’s advance notice of an encroaching forest fire. The Fire-Shield would be a modular, portable, inflated dome like those used for indoor tennis, which is prepared and custom-fitted to be later erected within a day. While typical inflated domes have their entire inner volume pressurized, our Fire-Shield will only require pressurizing a small volume contained between its double-walled structure that forms the dome as shown in Fig-1. The surface of its outer material uses NASA's radiatively reflective, aluminized Mylar to ward off the intense radiant heat of a fire storm. In addition this surface gets protected against the 100 – 150 MPH fire-winds, which are ready to impinge upon it, by injecting a high speed film of air (just like gas-turbine blades) produced by portable blowers. The actual heat-shield contains multiple, redundant pockets of cells directing the flow of air to both film-cool its surface and protect the shield against direct flame contact. Each major modular segment would contain its own portable, gasoline powered wind generator to supply the airflow. Depending upon home-size, several of these modules would be easily connected using Velcro plus redundant snaps and safety-stays. The shield gets attached over chimney tops and to pre-installed, grounded cement-posts, plus strategic hooks about the outside of the house. Special, inflated pillows are also strategically placed (between the shield and the house exterior) to facilitate the formation of a hemispherical shield that envelopes and protects our home against a high speed fire-storm. The Fire-Shield Design Concept The concept for a fire shield went through a gestation period of several decades as my career in thermo/fluids evolved. It started with the design of jet engine turbine cooling to thermal control of satellites, and finally to designing radiant heat barriers for cryogenics. These activities enabled receiving a score of patents as well. These activities inspired the concept for a rapidly deployable Fire-Shield to protect homes against a raging forest fire. The idea requires integrating several technologies ranging from inflatable commercial air domes to jet engine cooling to radiatively cooled spacecraft. Also included are flexible material coatings developed by NASA that radiatively reflects high temperature heat, making the deployable Fire-Shield a viable concept. Two key design principles are employed to protect both the heat shield and the home it envelopes. The first is shown in Fig-2 and uses a high speed film of air (faster than the anticipated fire-storm flame speeds of 100 – 150 MPH) that is locally directed to blow over the shield’s surface, cooling it and protecting it just like the metal turbine blades of jet-engines. The temperature of speeding flames impinging upon a jet engine’s metallic turbine blades is hot enough to easily melt them, yet the blades are protected by using this film cooling technology. The same technology will protect the heat-shield from meltdown when high speed flames of 100+ MPH attempt to impinge upon its surface. The second principle protects the shield against the intense radiant heat coming from a blazing forest fire where temperatures can exceed 2000 F. While this radiant heat does not physically touch the shield, as would a fire-storm’s flames, its presence is “felt” and is as deadly as the hot flames that would normally scrub over the shield without our film-cooling. We use a radiatively reflective, thermal coating barrier that repels this radiant heatload and protects the shield from melting. Such coatings were originally developed by NASA to protect satellites and spacecraft. The coating gets applied to the shield’s outer domed surface and will reflect better than 97% of all intensive radiant heatloads that are incident upon the dome’s surface. (Patent Pending; Original Concept Documented in 2006)  

Topic by RT-101 6 years ago