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Picture of DIY Hot Air Balloons
              Hot air balloons have been around since 1782 and are a well known way of transportation or for just viewing the geographical features of our modern world. Hot air balloons are also the oldest human-carrying flight technology ever. The way these balloons work is that heat is released into the balloon, and due to the fact that heat rises while cold air descends, when the balloon is heated internally, it will lift into the air and gradually rise higher when the passengers heat the inside.

In this instructable, I will be showing you how to make your own mini hot air balloon from just a few, cheap household items.
As you view this instructable, you will not only learn how to build the hot air balloon, but also learn the technology behind hot air balloons. This is a great hands-on learning experience that I use to teach my science class.

 
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Step 1: Materials

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Materials needed:

1- Large Plastic Bag(I used a bag from the dry cleaners)
3-4 Birthday candles
1-Thick and sturdy wire
1-Aluminum foil
1-Glue gun
1-Lighter

And of course some patience:)

Step 2: Tie The Bag

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First, Tie the bag in four evenly spaced spots by the opening of the bag
(see picture)

Then knot the top of the bag where the hole for the hangers is(only if you have a dry cleaners bag)

Step 3: Cut and Bend Wire

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Cut two pieces of wire that are about the same length as the knots on the bag that are diagonal from each other

Then, twist them together, forming an X shaped structure.

Step 4: Make the Candle Holder

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Take the aluminum, and make a cup shaped structure to hold the candles.

Step 5: Glue the Cup and Add Candles

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Hot glue the cup to the middle of the x shaped structure
Then glue 3-4 candles to the inside of the cup.

Step 6: Attach to Bag

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Carefully twist all 4 parts of the X shaped wire, to all 4 of the knots on the bag.

Step 7: Ready to Fly!

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Now here is where the fun begins!

Bring your hot air balloon to a calm, non windy area outside.

Then, make sure all areas of the bag arent touching or near the bag.

After that, light the candles on fire with the lighter and wait a while until the bag fills with hot air.

Finally when your bag is filled, let go of the bag and watch it rise in the air and get higher and higher.
These balloons have gotten so high, that I have even lost sight of them.
Try doing this at night for cool effects.

Be safe when doing this project, but most of all.... Have Fun!

Is this Instructable honestly advocating to litter our planet with plastic bags?? And from a SCIENCE TEACHER of all people, encouraging the destruction of our planet by sending non-biodegradable material up and "away" to end up in our rivers, streams, forests, oceans, etc. Many of these will inevitably becoming toxic substances confused for food by the rest of the creatures we share this planet with. Wow.... I hope my children's science "teachers" have a little more forethought than this.

I don't see anywhere in this instructable that says the teacher is encouraging students to release these into the wilds. Just because it floats doesn't mean they let them go. What the SCIENCE TEACER is advocating is hands-on learning, bringing dry textbook material to life. Isn't this what science is supposed to be about? And bravo to the teacher for encouraging the repurposing of materials.

AndreaS13- That must be because you didn't finish reading the instructions ;) If you keep reading you get to Step 7: "Finally when your bag is filled, let go of the bag and watch it rise in the air and get higher and higher. These balloons have gotten so high, that I have even lost sight of them." Doesn't sound like there's any string attached if they are disappearing. Science IS about hands on learning. It is NOT about destroying our planet by sending more pollutants into the environment. This science teacher should know better, and amend the Instructable to reflect his/her respect for our planet so as not to encourage others to follow his/her lead on apparently trashing the planet with plastic bags. Attach a string = problem solved.

Considering losing sight does not necessarily mean losing control I did not read this as untethered. Perhaps I was caught off guard by what I read as an attack on the teacher. I am an Environmental Educator/Advocate. I feel it's important that as we communicate our message of protecting the planet we don't alienate the people we are trying to educate.

I tied a string to mine, and pulled it back down when I was done, to prevent this from happening!

S3minol322 days ago
AWESOME!! my uncle is a science teacher. deffinatly recomending this to him!!
I myself am a teacher an have used this project to teach my students about cold air and warm air as i teach the weather unit. It is a great hands-on activity for the kids.
I want to do this project for my school. so I think that to control the ballon , we can fix magnet to alluminium and another to a long stick , so that we can control it.. how is the idea and I don't u think plastic burns..please science man reply fast... so I could do my project..
don't the plastic burn?????
harfbarf4 months ago

This is very good design it's really cool

Kr. Saurav2 years ago
Can't we make the balloon with paper strips?
It would also reduce the chances of melting.
Also, instead of the candles, you could soak some cotton in alcohol and burn it.
True, you would reduce the chances of melting … but increase the chances of the balloon catching fire in mid-air !!!… :)))

As for alcohol, I guess (but I may be wrong) that the heat produced is not as high as with candles …
yes, i have used tissue paper to make different shapes.
nof-z nof-z2 years ago
also, you can use charcoal
jhawkins141 year ago
What does "be safe" and "you must be cautious when doing this project" mean? What specifically can you do in terms of safety? Wait for a rain... Tie it with a string... Anything else?
1st thing 1st : use your head and good old common sense !!!… ;))

For instance : do NOT do this in a hot summer day when it has not been raining for 6 months and the land, grass, trees are dried up !!!
Do NOT do this in a Mediterranean pine forest !!!
Do NOT do this when there is a slight wind aiming to a gas station !!!
Do NOT do this near a marsh with dried reeds (this one I know 1st hand from when I was a kid in the 50's… and I still remember it …) !!!
Do NOT etc… 

Still there are plenty situations and places where you can do this safely … Great Inst'…
Thanks for posting !…

KD8MSS2 years ago
My Father did this back in 1965. It was a fun evening and we loved the reports of the UFO the next few days.

It was of course after a rain so nothing would catch fire if a balloon landed while the candles were burning.

Please don't do this if you live west of the Rocky Mountains. We are much to dry an environment to launch a flame into the air, where it lands I know not where. How about tethering the bag with a thread? Can somebody recommend a heat source that isn't an open flame?
Use the thinnest black garbage bags ( or thin thin liners), you can find use a stove pipe system for initial lift once up in very bright noon-1 pm sun it should stay up for a while. If you google solar balloons

you will find a number of sites like this one

http://www.solar-balloons.com/

If yu make a "smallish " one you can do an outer clear bag that has been inflated a bit and sealed, when the inner bag is inflated it will act as a double paned window and keeep in energy a tad longer (balloon in a balloon).

some cool foil makers on it will make it "visible" to radar, but I am not sure if this is good or bad.

if you can do it early in the day so you know you will get a long flight.
TheScienceMan (author)  hartmannsclass3 years ago
Good suggestion,but i dont live near the rockies
Velin93 years ago
Not to let you down or anything, but I think you copied this from "sciencetoymaker.com" because they have the exact same thing on their website
TheScienceMan (author)  Velin93 years ago
Its a known idea, i didnt copy
build523 years ago
Yep I tried doing this once but it didn't work out. Good job!!!!
TheScienceMan (author)  build523 years ago
It takes patience. Three of the biggest mistakes i have seen were
A- not enough candles
B-It weighed too much
C-Too big of a bag

Hope you try this again!
yeah I think my mistake was to thin of a bag.
wilgubeast3 years ago
Good academic connection. Also, that looks like a lot of fun.
TheScienceMan (author)  wilgubeast3 years ago
Thank you
rimar20003 years ago
Good work, but warning, doing that I almost fire the house...
TheScienceMan (author)  rimar20003 years ago
Yes, it is indeed a fire hazard and you must be cautious when doing this project.