| Author |
Message |
   
Thomas
| | Posted on Sunday, October 13, 2002 - 8:42 am: |      |
Is it possible to make a hot air balloon with some common household materials ? |
   
Simon Quellen Field (Sfield)
| | Posted on Sunday, October 13, 2002 - 1:56 pm: |      |
It is indeed! All you need is a lightweight material to hold the air. And if the bag of air is large, the material doesn't have to be very lightweight. This is because the lifting ability of the hot air goes up with the cube of the diameter of the bag, while the weight of the material goes up only with the square of the diameter. For small balloons, you can use very thin plastic bags, such as those dry cleaners use to keep the clean clothes from getting dirty on their way home. For larger balloons, some cheap garbage bags can be used (the cheap ones use a thinner plastic than the expensive ones). Often the thickness of the plastic is mentioned on the package. You want the thinnest material, since it will be the lightest weight. You also want the largest bag you can find. Stores that cater to people who move furniture sell big bags for keeping mattresses clean. Sometimes these bags are too thick and heavy, but you may find some lightweight ones. To fill the bag with hot air, first seal any holes with cellophane tape. Then seal the open end of the bag with more tape, leaving one small hole at the bottom. This hole should be large enoough to allow the nozzle of a hair dryer to fit into it. Fill the bag with hot air from the hair dryer. You may have to be careful not to let the hot air melt the bag. On a cool day with no wind, the bag should rise into the air and travel quite a distance before it cools and falls. If the bag is large and black, a hot sun will keep the air inside warm enough to provide lift for most of the day. Black bags absorb sunlight and convert it to heat. Clear bags won't do this. I would not recommend using birthday candles or other incendiary materials to keep the bag hot. When I was young it was popular to use soda straws in a cross at the open bottom of the dry cleaner bag, and to put birthday candles on the cross to make the bag rise. I am certain that this caused fires on occasion, although ours always burned out high in the air. The hair dryer is a safer way to fill the bag. Simon |
   
Thomas
| | Posted on Monday, October 14, 2002 - 12:36 pm: |      |
Thanks ! I'll try it as soon as possible ! |
   
Eelco
| | Posted on Wednesday, November 27, 2002 - 10:45 am: |      |
or mess around with a garbagebag, some liquid plummer (NaOH), aluminium foil and somekind of coolingdevice |
   
Simon Quellen Field (Sfield)
| | Posted on Wednesday, November 27, 2002 - 6:57 pm: |      |
Of course that would be a hydrogen balloon, not a hot air balloon. Lye (the NaOH mentioned above) is pretty dangerous stuff. It can start the water boiling if added too quickly, and a splash in the eye can cause blindness. It will eat away clothes and skin if not washed off quickly. It would also be a good idea to keep the bag away from flames. |
   
BlackArT
| | Posted on Friday, February 7, 2003 - 9:39 am: |      |
If the days are usually hot make the bag a black one else use white. The reason is that black is a good absorber of heat but also a good emiter, therefore on a cold day the black bag won't be able to absorb any heat but it will be able to emit it thus the temp of the bag will fall quickly. For the white bags is vice-versa. |
   
yipster
| | Posted on Thursday, February 20, 2003 - 4:36 pm: |      |
aldo not a balloon we use to make knots in the bag and hang it from a brigde or balcony. when lit it burns away slowly dropping burning plastic drops that sound "phhhiiiiiieeeeeeeepppp" in a bucket with water. for balloons i used spirited sugar cubes or bbq lichter, at night you can follow the balloon that way... |
   
Anonymous
| | Posted on Tuesday, May 6, 2003 - 10:34 pm: |      |
i tryed using s bag and hair dryer but it dident flote. would candles make the air hotter in the bag? |
   
Simon Quellen Field (Sfield)
| | Posted on Wednesday, May 7, 2003 - 1:10 am: |      |
Try a larger and/or thinner bag. Something like this or this works great. Candles are a bad idea. The result is an uncontrollable incendiary device. |
   
Anonymous
| | Posted on Saturday, May 10, 2003 - 11:23 pm: |      |
ok thanks |
   
Anonymous
| | Posted on Sunday, October 5, 2003 - 9:09 pm: |      |
I have made a hot air balloon as a school project. We used tissue paper and made a paturm for the gores. we had a purpose built propane heater for launching them but i have heard of people useing a buch of candles suspented under the balloon. this could be reasonably safe if it was done in the winter when there is lots of snow on the ground. If one of these balloons is flown at night they are suposed to resemble a flying saucer. Try putting "fire ballons" into a seach engine for more info. |
   
Simon Quellen Field (Sfield)
| | Posted on Sunday, October 5, 2003 - 10:30 pm: |      |
Get permission from your local police and fire departments before launching flaming things into the air. The penalties for burning down houses (perhaps with people in them) are pretty severe. |
   
Anonymous
| | Posted on Wednesday, December 17, 2003 - 5:56 pm: |      |
Here's all the info you need: http://www.overflite.com I've made my own, and flown it. It used a 2 foot, by 2.5 foot bag with 12 birthday candles. It's first flight flew over a major road, in rush hour, over powerlines and into someones tree. Then I recovered it as the wind blew it back across the road. learning from my mistake I rebuilt, and launched it recently on a frozen lake away from anyone. It successfully went up, and away. One of you guys were saying a black bag would work best, but the problem with that is, you want the lightest bag that can still keep from overheating and melting. Black would absorb alot of heat, and you'd be forced to used less candles, in my case more like 5 before it would burn. Any way, i thought it was cool, but keep it safe. Even if you don't feel wind, believe me... it's there, possibly above the treeline. |
   
Simon Quellen Field (Sfield)
| | Posted on Wednesday, December 17, 2003 - 6:20 pm: |      |
I still prefer the solar balloons. Solar power doesn't ignite wildfires and kill people. The links I posted above will get you there. What you want is not necessarily the lightest bag material. The weight of a spherical bag goes up with the square of the diameter of the bag. The amount the bag can lift goes up with the cube of the diameter. So simply increasing the diameter will quickly overcome any problem with the weight of the bag material. The solar powered bags will also stay up all day, while the candles will go out fairly soon. Lastly, the candles weigh more than the bag to start with. |
   
Anonymous
| | Posted on Friday, December 19, 2003 - 8:27 pm: |      |
Ok you don't always need the lightest bag material, but if you double the thickness of the plastic, you'll need like 3 times the diameter (just taking a guess here). Anyway... can you build solar balloons? I mean would you use a huge garbage bag or something? I've never even heard of solar balloons till like yesterday from your posts. |
   
Anonymous
| | Posted on Friday, December 19, 2003 - 8:31 pm: |      |
Bigger isn't always better... "Tragedy strikes as a boeing 747 hits a massive solar balloon, experts predict the plane to come down some time around nightfall" lol just kidding |
   
Simon Quellen Field (Sfield)
| | Posted on Friday, December 19, 2003 - 9:18 pm: |      |
A 30 gallon trash bag is 4 cubic feet, or 0.11 cubic meters. Say a 30 gallon bag of some thickness X is filled with hot air and is negatively buoyant. If we double the thickness, we need to double the volume of gas in order to lift the bag. A 60 gallon trash bag would be needed, or 8 cubic feet. To make the calculations easier, let's assume the bag is a cylinder. It is easy to see that simply doubling the height of the cylinder will double the volume. If the cylinder has a radius of 6.75 inches and is 4 feet tall, it holds 4 cubic feet. We can double the volume by increasing the radius to 9.5 inches. This is far from 3 times the diameter. It gets even simpler if the bag is a sphere, like a rubber balloon. If the balloon is 11.82 inches in radius, then the volume is 4 cubic feet. To double the volume to 8 cubic feet, we increase the radius to 14.9 inches. This is nowhere near three times. As the volume increases with the cube of the radius, the surface only increases with the square of the radius. Since the surface is the only component that adds weight, and the volume is what determines lift, the radius does not have to increase very much to lift twice as much weight. You can get solar balloons here. |
   
Anonymous
| | Posted on Sunday, December 21, 2003 - 1:36 am: |      |
ok.. that makes sense for solar balloons, but when you get into candle balloons, then you have to double the candles, to heat that amount of air... then you need a bigger frame to keep a good 4 inches away from the flames etc etc.... And then when it gets really big, you say, hey I wonder if a video camera would fit on that, maybe a little tracking device, or how about a doll Whatever...... Pretty much, I prefer small balloons. The smaller, the better. And as for fire hazards, well I live in minnesota. It's 20 degrees out. I couldn't even get the 12 inch butane lighter to get a spark until it was warmed up. |
   
Simon Quellen Field (Sfield)
| | Posted on Sunday, December 21, 2003 - 1:59 pm: |      |
Here is warm, dry, sunny California, we worry about brush fires and forest fires, which have recently caused billions of dollars in damage and many lost lives. The arsonists who started those fires face severe penalties, and some are being charged with murder. It is not a good idea to launch incendiary devices into the air, where you cannot control them. |
   
Anonymous
| | Posted on Sunday, December 21, 2003 - 4:35 pm: |      |
Safety is always important. But how about that massive 50 foot balloon on the webpage. What happens if it hits a small plane at 120 mph. If it got stuck on the front of a small cessna, the drag could easily crash it. It might even wreck a 737's engine. What happens when that 50 foot balloon comes down at night on a major road. What if it lands in powerlines, and the whole bag goes up in flames. Launching anything in the sky is dangerous. I consider the danger less so when launched in the middle of a frozen lake the size of several football field, in 12 inch snow, at 20 degrees with a balloon just bigger then a shopping bag. |
   
Simon Quellen Field (Sfield)
| | Posted on Sunday, December 21, 2003 - 4:50 pm: |      |
First of all, the solar bags aren't flaming. The chance of one being hit by an airplane is vanishingly small. The chance of the candles coming down to the ground is near certainty. But more to the point, someone paying $20 for a solar balloon is much more likely to keep it on its string than to let it go. |
   
Anonymous
| | Posted on Monday, December 29, 2003 - 2:50 pm: |      |
Funny, I put mine on a string, and it barely ever touched the ground. |
   
ryan from sydney
| | Posted on Tuesday, June 1, 2004 - 7:46 am: |      |
you can also use 240 litre garbage bags and use tie wire to form a ring for the opening then put a strand of wire accross the ring in one direction and one in the opposite to create a bulls eye pattern before you join the last crosswire on thread bbq igniter cubes onto the wire and slide into the middle for a 240l bag 2 cubes are ample for enough heat to get it up into the clouds and drift far enough that you cant see it anymore now attatch the ring to the inside of the bag (just inside the opening, folded over the wire about half an inch)with sticky tape and then turn the bag upside down light the cubes support the top of the bag until hot enough to support itself then let go of the bottom and laugh yourself silly as it drifts up into the clouds... |
   
dingaling
| | Posted on Wednesday, July 14, 2004 - 4:12 am: |      |
dern younguns always trying to start trouble, hehe... You can take extremely cheap almost see thru garbage black garbage bags and just tie them with a thread leave outside on a day when its feels nice outside but you know the sun is just beaming down.... and there you have it. a completely effortless ufo... |
   
Anonymous
| | Posted on Saturday, October 2, 2004 - 7:21 pm: |      |
you could use an aircannon to put out the candles from a distance |
   
kaushik
Unregistered guest
| | Posted on Monday, December 27, 2004 - 1:13 pm: |      |
hey ! I got some really cool info frm this site..but I want one of u to squeeze ur brains on this one. well I'm having a school project where I'm supposed to make a hot air balloon with its maximum dimension not exceeding 1m cube..which must include the plastic bag and the frame as well.I want suggestion from you guys to help me build one.The balloon is expected to fly at an altitude of only 15m and single or double engines can be used...the frame can also be the "H" type or "x" type..the source of power is again birthday candles and the balloon is expected to carry a very minimal load..can u please tell me the " how to s" for this balloon? thanks a million! |
   
lysdexia Unregistered guest
| | Posted on Monday, December 27, 2004 - 1:43 pm: |      |
how-to's Glue some bags together at their ends and cut out their common walls. |
   
Anonymous
| | Posted on Wednesday, January 12, 2005 - 1:51 am: |      |
if expecting a candle powered balloon, *small* to carry any kind of extra weight, the balloon's going to have to be pretty large.. if the weight is merely a small, paper basket under the H frame or X, will work. what is it exactly you are trying to lift? *added weight in the form of payload means that you must make your balloon much larger in volume for added.. Buoyency.. |
   
Anonymous
| | Posted on Wednesday, January 12, 2005 - 1:54 am: |      |
additionally, using tape to hold the balloon together works if you decide to get elaborate, and make *Gores* that decide the shape of the balloon once inflated. a traditional, upside down tear drop shape may work best.. ah, and to add to the complexity, you'd have to make the balloon much larger as it has to now carry tape as part of its overall construction. |
   
Anonymous
| | Posted on Saturday, April 23, 2005 - 10:17 pm: |      |
just today i successfully lauched a semi-controllable hot air balloon made out of staws safty wire and a dry cleaning bag. I used a cotton ball, sprayed it with pyro oil an d used this as my fuel. it flaoted until the fuel burned down. When my dad tried to refuel it in mid-air it burned up. I'll try again tommorrow. |
   
jessica fin
Unregistered guest
| | Posted on Wednesday, June 29, 2005 - 3:30 pm: |      |
wow lots of great info here - i was wondering if anyone has seen instructions to build solar garbage bag balloon that will llift 1 person? --- any reccomendations about this? thanks!! |
   
Simon Quellen Field (Sfield)
Senior Member Username: Sfield
Post Number: 533 Registered: 12-2004
| | Posted on Wednesday, June 29, 2005 - 6:37 pm: |      |
See this answer. |
   
Michael S Unregistered guest Posted From: 64.220.70.2
| | Posted on Monday, August 15, 2005 - 4:14 pm: |      |
One of the best bags I used for a hair-dryer balloon is those flimsy things that your suits and dresses come back in from the cleaners. Very light, very easy to get a hold of, and not a big investment lost if it gets caught in a tree. |
   
Anonymous Posted From: 68.44.221.6
| | Posted on Wednesday, August 17, 2005 - 12:47 pm: |      |
i built 2 tissue paper balloons, one about 1 foot cubed and the other about 2ft^3. i made a wire rim and a plastic platform. the first time i put a tea candle on it and the second time i put a tea candle and 4 birthday candles. Neither flew. I don't know if it was too hot (78*F), or the balloon wasn't big enough, but neither even felt like it lifted. How can i build a generally small tissue paper hot air balloon that can lift with a candle and be tethered to a string. I would really appreciate some help. |
   
Marat Orazov (Marat_o)
Intermediate Member Username: Marat_o
Post Number: 30 Registered: 6-2005
| | Posted on Wednesday, August 17, 2005 - 2:32 pm: |      |
I think the reason neither of them flew is because they were too heavy. A wire rim and a plastic platform, that is a considerable amount of weight, not to mention the birthday candles, how big was the tea candle, if its bigger than the birthday candles, maybe you are better off with using 5 birthday candles instead of the arangment you have above, and considering the amount of weight you have, you do need a larger balloon. |
   
Simon Quellen Field (Sfield)
Senior Member Username: Sfield
Post Number: 638 Registered: 12-2004
| | Posted on Wednesday, August 17, 2005 - 5:54 pm: |      |
At the risk of repeating myself (again) I would like to point out that the math for figuring out the lift of your balloon has already been described in detail. |
   
Simon Quellen Field (Sfield)
Senior Member Username: Sfield
Post Number: 639 Registered: 12-2004
| | Posted on Wednesday, August 17, 2005 - 6:01 pm: |      |
In case the math scares people, just remember that a cubic foot of air at 120 degrees can lift an eighth of an ounce (3.6 grams) if the outside air is 65 degrees. So, find out how many cubic feet are in your balloon, and multiply that by 0.128 to get the number of ounces it can lift (or by 3.6 to get the number of grams it can lift). I suspect that the tissue paper and glue for a 1 cubic foot balloon weigh more than an eighth of an ounce, without the wire rim and plastic and candle. A birthday candle is pretty heavy -- you might want to leave it on the ground as the balloon rises above it. |
   
Matt D Unregistered guest Posted From: 210.11.188.16
| | Posted on Thursday, September 1, 2005 - 7:53 pm: |      |
i have made hotair balloons using a garbage bag and a circular wire frame around the base. very light wire, like what is found in CAT5 cables witht he plastic burnt off. Then a crossshape with a thing in the middle so it bends d ownwards. in there you put some cotton wool balls soaked in metho. it flew about 4-5 kilometres. |
   
Anonymous Posted From: 24.206.85.109
| | Posted on Monday, September 12, 2005 - 12:16 am: |      |
Hell.Stop whining about danger of candles .Who wants a air ballon filled up with hot air from hair dryer. Let me tell ya.I made a few test flights in my garage.I made sure it's cool,about 69 F then took two trash bags:one i cut the botto off. Then i took the one i cut and taped it to the one i havent cut .Then i had an 8 feet tall,two and half feet wide cylinder.I taped a drinking straw in to H-frame and metled 6 cake candles. Then took it to the frien'd house where i was clean of trees ,filled bag with air,lit the candles and let the bag fly away.It started rising rather slow and gentle but most definately rising.Before too long it was high enough to clear the house and by the time it burned down you only saw a flickering of the flame.I am sure it wouldnt start no fire if you use a common sence.And if you are a ****deleted by administrator**** you could even break your ****deleted by administrator****! Enjoy your HOT AIR CANDLE powered balloon. Peace. |
   
Anonymous Posted From: 65.57.245.11
| | Posted on Monday, September 12, 2005 - 10:45 am: |      |
The penalties in my area for launching incendiary devices into the air are 10 years to life, depending on how many people you kill with the fire you start. Arson is taken seriously here. Common sense says you should not light something on fire and then send it off where you can't control what happens to it. Sudden gusts of wind that overturn the balloon will bring the flame next to the bag, setting the whole thing ablaze, and now you have a large flaming ball of plastic landing in a tree or in some dry grass. Burning down a house by being stupid gets you put in a place where doing stupid things can't harm the rest of us. I'm just glad your spelling and grammar show people just how ignorant you are. |
   
justine aquino (Unregistered Guest) Unregistered guest Posted From: 202.78.104.191
| | Posted on Friday, December 2, 2005 - 6:23 pm: |      |
why dont you just use small bag,with a small oil lamp,with small wooden frame?..simple as that ive tried it trust me i'll send you some pics after i get my camera back from my friend...its cool to make several small candle then send them by swarms with a small surveillance camera on board(just joking)its impassoble for it to carry a 15 g. cam on board..and your gonna be wasting money if the wind blew the camera somewhere there |
   
Simon Quellen Field (Sfield)
Senior Member Username: Sfield
Post Number: 798 Registered: 12-2004
| | Posted on Saturday, December 3, 2005 - 2:49 pm: |      |
As I have said before, launching uncontrolled incendiary devices into the air is not only a bad idea, it is against the law. |
   
Anonymous (Unregistered Guest) Unregistered guest Posted From: 72.235.129.42
| | Posted on Saturday, December 24, 2005 - 6:02 pm: |      |
why not try a 12 volt hair dryer and some very light batteries nimh or the paper thin solar panel that weigh on 2 oz for a 5 watt 12 volt panel WWW.siliconsolar.com |
   
Megan Crane (Unregistered Guest) Unregistered guest Posted From: 66.82.9.67
| | Posted on Thursday, December 29, 2005 - 5:04 pm: |      |
For school I have to make a hot air balloon made out of parchment paper and heating it with a tea lite candle. I can use string and only supplies like scissors and a pencil. But I can't make it fly I have done this a few times and each time it catches on fire. I made them in a shape of a cone. I need some ideas on how to make it fly. Thanks! |
   
Simon Quellen Field (Sfield)
Senior Member Username: Sfield
Post Number: 861 Registered: 12-2004
| | Posted on Thursday, December 29, 2005 - 5:32 pm: |      |
Parchment paper sounds a little heavy. A dry cleaning bag is what is usually used. You use a little tape to close up any holes in the top part, and spread the bottom part out using paper straws. The straws help to keep the open bottom part facing down, so the hot air doesn't leak out. To make one out of paper, you would want to make it as spherical as you can, since a sphere holds the most hot air for the amount of heavy paper you would need. There are some paper balloon sites on the internet you can look at for ideas. You probably want to use tissue paper instead of parchment paper. |
   
justine aquino (Mnado)
Intermediate Member Username: Mnado
Post Number: 46 Registered: 12-2005
| | Posted on Thursday, December 29, 2005 - 7:02 pm: |      |
whoa,parchment paper?that as heavy as a construction paper dude!you can use a creep paper or japanese paper for this(if your gonna use japanese paper you might want to make it round and dont let the fire gett near to the paper,it easily gets on fire)and using a small plastic is not ideal it melts down it doesnt fly! |
   
Balloonist (Unregistered Guest) Unregistered guest Posted From: 152.53.30.65
| | Posted on Wednesday, January 4, 2006 - 12:35 pm: |      |
I'm trying to make a hot air balloon for a Science Fair Project and I'm looking for the best type of materials and best way to heat it. I've read through a bunch of posts and even with the problem of melting bags and fires I think that using birthday candles would have the best result and be most interesting in a poject. I'm wondering if any one can fill me in on ways to keep it safe. Thanks PS. would tieing the base of the balloon to something like a kite string be good? I'm going for "can it fly easily?" more than "how far can it fly?" |
   
Simon Quellen Field (Sfield)
Senior Member Username: Sfield
Post Number: 877 Registered: 12-2004
| | Posted on Wednesday, January 4, 2006 - 12:56 pm: |      |
I'd go with the large black solar balloon. Guaranteed to work, and you won't have to convince the Sceince Fair committee to let you use fire. |
   
Balloonist (Unregistered Guest) Unregistered guest Posted From: 152.53.30.65
| | Posted on Friday, January 6, 2006 - 9:24 am: |      |
Ok great thanks. I think I'll use the solar balloons and the candle ones just for some variety. I shouldnt have trouble with the Science Fair people because my idea has already been okayed by my teacher. I've got a few ideas about how to meet saftey regulations. |
   
bullrider (Unregistered Guest) Unregistered guest Posted From: 72.16.26.177
| | Posted on Tuesday, January 10, 2006 - 3:06 pm: |      |
why cant you do this inside because when i tried it failed |
   
Alexander N Roberts (Whoo_mythbusters)
Intermediate Member Username: Whoo_mythbusters
Post Number: 32 Registered: 9-2005
| | Posted on Tuesday, January 10, 2006 - 4:38 pm: |      |
because the solar ballon is using the heat from the sun to lift itsself..... an artificial light sorce would have to be really big and give off alot of heat |
   
Simon Quellen Field (Sfield)
Senior Member Username: Sfield
Post Number: 904 Registered: 12-2004
| | Posted on Tuesday, January 10, 2006 - 4:40 pm: |      |
The density of air is proportional to the absolute temperature. Suppose the temperature in your house is 24 degrees Celsius. That is an absolute temperature of 297.15 degrees Kelvin. Now suppose your balloon contains 100 liters of air, and weighs 10 grams. Suppose also that the air in the balloon weighs about 1 gram per liter, so we have 110 grams total weight (balloon plus air). To lift the balloon, the total has to be less than 100 grams, since that is the weight of the equivalent volume of air. So the air inside the balloon must weigh less than 90 grams. So, we must heat the air until it is 100/90 times hotter than the outside air. That is 1.1111 times hotter than 297.15, or 330 degrees Kelvin, or about 57 degrees Celsius (134 Fahrenheit). At this temperature, the balloon will be weightless. Raising the temperature will cause it to rise. If you are outside in the evening, where the temperature is 278 degrees Kelvin, then you only need to raise the temperature of the air in the balloon to 100/90 * 278 degrees, or 308 degrees Kelvin (about 35 C, or 96 F). It is a lot easier to heat the air in the balloon to 96 Fahrenheit than to 134 Fahrenheit. So go outside. |
   
Wow, ya'll know a lot! (Unregistered Guest) Unregistered guest Posted From: 152.53.30.65
| | Posted on Wednesday, January 11, 2006 - 12:15 pm: |      |
geez and crackers |
   
Devlon (Unregistered Guest)
Unregistered guest Posted From: 205.188.116.13
| | Posted on Thursday, January 26, 2006 - 11:15 pm: |      |
My daughter (3rd grade) wants to enter a science fair at school. We really don't have to experiment with building our own mini hot air balloon. Is anyone aware of any pre-made mini hot air balloons or balloon kits? Thanks, Devlon Bignault |
   
Science Fairest (Unregistered Guest) Unregistered guest Posted From: 152.53.30.65
| | Posted on Friday, February 3, 2006 - 11:14 am: |      |
Hey, I'm having trouble finding a calm enough day to float my candle balloon. If I found a big enough building could I fly it inside and get the same results? Also if inside won't work what would be the calmest time of day to fly it? I'm doing this for a science fair and I only have a limited amount of time to do my experiment. If you have any information of ideas I would like to hear from you. Thankyou. |
   
Simon Quellen Field (Sfield)
Senior Member Username: Sfield
Post Number: 973 Registered: 12-2004
| | Posted on Friday, February 3, 2006 - 12:58 pm: |      |
We've shown you how to do the calculations. Measure the temperature inside the room. Then measure the temperature inside the bag. You can then calculate the lift. Weigh the bag, and you will then know if it will rise or fall. |
   
matthewdontcare@hotmail.com (Unregistered Guest) Unregistered guest Posted From: 62.31.69.58
| | Posted on Saturday, February 4, 2006 - 5:59 pm: |      |
The mass of a hot-air balloon and its occupants is 320kg (excluding the hot air inside the balloon). The air outside the balloon has a pressure of 1.01 X 10^5 Pa and a density of 1.29 kg/m^3. To lift off, the air inside the balloon is heated. The volume of the heated balloon is 650 m^3. The pressure of the heated air remains the same as that of the outside air. To what temperature (in kelvins) must the air be heated so that the balloon just lifts off? The molecular mass of air is 29 u. please work this out asap |
   
Simon Quellen Field (Sfield)
Senior Member Username: Sfield
Post Number: 995 Registered: 12-2004
| | Posted on Saturday, February 4, 2006 - 7:32 pm: |      |
If you need a calculator, Google has one built-in. Just type your homework assignment into the Google search bar as a valid arithmetic expression, and it will show you the answer. It will even get all of the unit conversions right for you. But don't expect us to do your homework for you. |
   
please help (Unregistered Guest) Unregistered guest Posted From: 62.31.69.58
| | Posted on Sunday, February 5, 2006 - 12:42 pm: |      |
its not home work its a cpmpertion for a free air ride please |
   
Simon Quellen Field (Sfield)
Senior Member Username: Sfield
Post Number: 1009 Registered: 12-2004
| | Posted on Monday, February 6, 2006 - 1:04 am: |      |
Why should we help you cheat? All of the information you need is in front of you. If you can't do the arithmetic, you don't deserve to win. |
   
chris banta (Christopher)
New member Username: Christopher
Post Number: 1 Registered: 3-2006
| | Posted on Friday, March 24, 2006 - 1:35 pm: |      |
hey i have experience with large plastic hot air balloons a friend and i, bored at school one day thought it would be fun to make a large hot air balloon and when a sweet idea comes to my attention i usualy follow through with it, that and i had extra study halls, so with the blessing of my physics teacher i was able to get out of study hall and work on nate and I's giant hot air balloon. it took a few weeks but the end result was a large cilindrical hot air balloon with about a 20 foot diameter and about 60 feet long, it was an amazing thing we actualy inflated it in the school hallway and had class inside the balloon. we went out to a friends farm and used a diesel powered redi heater to fill the balloon on a nice cold day, we learned a lesson the first time we launched it, DON'T PUT HEAVY METAL OBJECTS ON YOUR BALLOON THEY CAN FALL OFF. it nearly missed my friends house, and dog. but anyways we used several sheets of think painters drop cloth found at the local walmart, menards has mega rolls that work out great for balloons, and packaging tape. both work well. if you want a simple easy balloon, around christmass time walmart carries "chrismas tree disposal bags" they are 97 cents each and work great just tape the small hole for the tree trunk shut and a hairdryer works great to fill them, as does a small torch. (Message edited by christopher on March 24, 2006) |
   
tooths d' ache (Tooths)
New member Username: Tooths
Post Number: 1 Registered: 1-2007
| | Posted on Monday, January 29, 2007 - 5:44 am: |      |
Ei! Can i ask something? what object/s can this air balloon lift? Can these lift small things like: baskets, bottles, etc.? Pls. answer this! I need a sample for my air-balloon project! My teacher asked me a demonstration. Pls. help me! I kno you can do this! G2g! |
   
Simon Quellen Field (Sfield)
Senior Member Username: Sfield
Post Number: 1626 Registered: 12-2004
| | Posted on Monday, January 29, 2007 - 10:35 am: |      |
It's a long thread, so I'm not surprised you didn't read it all. If you had, you would have found this answer: "http://scitoys.com/board/messages/9/968.html?1120084524". |
   
... (Tre_confused)
New member Username: Tre_confused
Post Number: 1 Registered: 1-2008
| | Posted on Sunday, January 6, 2008 - 3:11 pm: |      |
well, i read the whole tread. i am still way confused. im working with my dad right now on my science fair project. i broke my leg the week before we were planning on starting, so now he has to help. and now he wants me to gather lots of different instructions on different ways to create a hot air balloon. i dont want a solar balloon though. we are having trouble getting it to stay in the air. we have a dry cleaner's bag and we have a hair dryer. we filled the bag with hot air from the dryer, let go after we seal the bottom. then, well, it goes down, and hits the ground. soo, i cant get it to work. suggestions? it would be appreciated. |
   
Simon Quellen Field (Sfield)
Senior Member Username: Sfield
Post Number: 1825 Registered: 12-2004
| | Posted on Sunday, January 6, 2008 - 4:40 pm: |      |
You need a bigger bag, hotter air, or a lighter bag. The bags they put on mattresses before they move them are nice and big, and you can get them at a mover's supply store. |
   
Rohan (Digital)
New member Username: Digital
Post Number: 1 Registered: 3-2008
| | Posted on Monday, March 10, 2008 - 2:52 am: |      |
are candles not a good idea ???????????? |
   
Theresa Simmons (Theresa)
Intermediate Member Username: Theresa
Post Number: 24 Registered: 1-2008
| | Posted on Monday, March 10, 2008 - 10:31 am: |      |
Candles are not a good idea. You have no control of where the balloon will land once you launch it. Having a bunch of flaming wax and plastic land on someone's house or tree (or head) is not good. If you kill someone by burning their house down, there is no way to undo the damage. |
   
Rohan (Digital)
Junior Member Username: Digital
Post Number: 6 Registered: 3-2008
| | Posted on Tuesday, March 11, 2008 - 1:24 am: |      |
HEY IN INDIA WE DONT BUILD HOUSE OF WOODS INSTEAD CONCREATE. A CANDLE WONT BURN DOW A CONCREATE HAHA HAHA HAHA HAHA LOL |
   
Kasper Emil Feld (Magnetfeld)
Advanced Member Username: Magnetfeld
Post Number: 69 Registered: 11-2007
| | Posted on Tuesday, March 11, 2008 - 2:29 am: |      |
We build houses of bricks or concrete to. There are still a lot of wood in a house. Do you live on a concrete floor? There are probably wood and trees around the houses to. Fire can severely dammage bricks and concrete. |
   
Rohan (Digital)
Junior Member Username: Digital
Post Number: 7 Registered: 3-2008
| | Posted on Tuesday, March 11, 2008 - 8:47 am: |      |
YES every thing is made up of concreate floor also. in india there is no such house (as per i am seen) made up of wood. YES the windows or doors are made up of wood. but in my terms i dont thing a birthday candle would burn a door or a big window. so kasper where are u from? tell abt ur country? BIRTHDAY CANDLES DAMAGING CONCREATE OR BRICKS......... GONE MAD OR WHAT ? DO U KNOW HOW A BRICK IS MADE? WELL FOR YOUR KNOWLEDGE BRICKS ARE GIVEN THIER STRONGNESS BY FIRE SO THERE IS NO PROBLEM. THE ROCKET LAUCNCHING PAD IS ALSO MADE UP PF CPNCREATE AND THEN THE FIRE OF THE ROCKET DOES NOT DAMAGES THE BASE. THERE IS NO PROBLEM IN INDIA. BUT IN UR CASE I DONT KNOW. |
   
Theresa Simmons (Theresa)
Intermediate Member Username: Theresa
Post Number: 26 Registered: 1-2008
| | Posted on Tuesday, March 11, 2008 - 10:31 am: |      |
Don't be an idiot. Especially when we're talking about fire safety and doing irresponsible things that can kill people. There's a fire station near you. Why is that? Go ask them if they think it is a good idea to launch flaming material into the air. "http://news.bbc.co.uk/2/hi/south_asia/7186500.stm" "http://www.fire.uni-freiburg.de/photos/in/in.htm" "http://news.xinhuanet.com/english/2008-03/10/content_7760026.htm" "http://www.abc.net.au/news/stories/2008/01/12/2137230.htm" "http://query.nytimes.com/gst/fullpage.html?res=9C07E6DD1E39F930A15752C0A9629C8B63" "http://query.nytimes.com/gst/fullpage.html?res=9D07E1D81539F935A15751C1A963958260" "http://www.yarnsandfibers.com/news/index_fullstory.php3?id=14770&p_type=Cotton" "http://www.crowddynamics.com/Disasters/india__wai_fire_2005.htm" "http://www.salvationarmy.org/ihq/www_sa.nsf/vw-news/C53FA61E2444E97D802572970058EE1F?opendocument" "http://blogs.usatoday.com/ondeadline/2006/04/how_many_dead_i.html" |
   
Rohan (Digital)
Junior Member Username: Digital
Post Number: 9 Registered: 3-2008
| | Posted on Tuesday, March 11, 2008 - 2:07 pm: |      |
Rules and "Netiquette" When writing your messages, please use the same courtesy that you would show when speaking face-to-face with someone. Flames, insults, and personal attacks will not be tolerated. It's fine to disagree strongly with opinions, ideas, and facts, but always with respect for the other person. Great minds do not always think alike, and that's where the fun is! Also, note that messages express the thoughts of the writers, not the board or its moderators. |
   
Alok Mehta (Alok)
New member Username: Alok
Post Number: 2 Registered: 10-2008
| | Posted on Monday, October 13, 2008 - 2:53 am: |      |
Hi Rohan, Its true that most buildings in India are made of brick concrete -but that not the only thing where the Hot air ballon with a candle might land??? If the ballon crashes on a forest/grassland during indian summers /wheat or sugarcane field --???? You dont want to imagine the loss it may cause???? |