This instructable will teach you how to successfully make hot air balloons on a small scale. You can do anything you want with these balloons! They can be used as kites for days when the wind is not around to fly yours, and they are a really fun project for children, that they can learn from as well as enjoy. Make sure, however, if you are working with younger kids, that you handle the cutting and the lighter for them. This project can also be a fun and interesting science project or side experiment at any age!

Disclaimer: Our experiment did not work as well as it could have, so in order to lighten the balloon, we have adjusted the measurements and materials accordingly. The pictures, however, reflect the original design.

Supplies

A 1 inch by 9 inch by 1/16 inch strip of balsa wood (You can find Balsa wood at most craft or hardware stores like Michael's, Joann, and Home Depot)
Utility knife
Cutting mat
Two thin plastic grocery bags (If you want to personalize them later on, use light colored bags)
Birthday candles (You will only use four, but it's always good to have extras)
Long matches
Hot glue
Scotch tape
Dental floss
A weight to tie on to the end of the floss in case you accidentally let go. I recommend using a washer or nut because most people have them around the house, and they are really easy to tie on to the string.
Spray paint (optional)
Small cup--diameter is flexible; about a two inch wide base is good. Any lightweight plastic cup will work, for example a yogurt cup or Dixie cup.

Step 1: Making the Frame

For this step, you will want to have your balsa wood out, along with the utility knife, ruler, and your cutting mat.

Warning: This does involve a knife, and will be dangerous if done improperly. Be very careful when you are cutting!

Because most stores will not sell balsa wood with such specific measurements, you will probably have to trim yours to size. Use the ruler as a straightedge and cut the strip using the utility knife. Make sure you use the ruler to get a straight edge. Cut two 1/2 inch by 9 inch pieces from the wood. If you use the ruler as a straightedge, they will be perfect rectangles.

Now, mark the middle of each strip with a small dot (at 4.5 inches). Using hot glue, dab a small amount (about the size of a pea on each dot, and then stick the pieces together perpendicular to each other. The two dots should both be sticking to each other, and the pieces of wood should now form a cross. Tie the floss to the center of the cross and fasten the nut/washer to the other end. Once your frame looks like the picture above, with shorter pieces and without the square in the middle, you are done with this step!

Step 2: Making the Parachute

For this step, get your plastic bags, tape, scissors, and ??? wire.

For the sake of this instructable, I will refer to the bags as Bag 1 and Bag 2. Make sure you don't get the two bags mixed up. Before you begin, check your bags for holes and patch any you find with tape. To start on your parachute, first cut the handles off of Bag 1. Be sure that you DO NOT THROW THEM AWAY! You will use them later on in this step. Also, make sure that you cut them off in a way that still leaves behind a bag, just without handles. Set the handles off to the side while you do the next step.

Take Bag 2 and cut the bottom of the bag off. Take only the bottom few inches; leave the middle part and handles. Once your bags are both cut, take Bag 1 and put it around the cut off part of Bag 2. It should form a strange, elongated bag. Tape the two together, making sure you tape on the inside and the outside of the bags. It is important to put Bag 1 on the outside of Bag 2. If the lip of Bag 2 is on the outside, your hot air balloon will not be efficient, and may not work at all. Now tape your extra handles onto Bag 2, adjacent to the ones that are already there. You should end up with a long bag that has a total of four handles, one every 90 degrees.

Step 3: The "basket"

This step requires your cup, birthday candles, and the hot glue gun. Remember to be very careful with the hot glue gun, because if you touch the metal, it will burn you.

Use the utility knife to carefully cut your cup to size--it needs to be one inch tall.

Get a candle, and once your hot glue is ready, put a little bit on the end of it. (Opposite the wick) Put the candle in the cup, leaving some space in the bottom to fit the other three. Do not light the candle yet. Just put it in the bottom of your cup and then repeat this step for each candle. Once all four candles are in the cup, set it to the side to let the glue dry.

Step 4: Finalizing!

You're almost done! After this step, you'll have a fully functional hot air balloon.

Use tape to attach your cup to the wood frame. After you have put the cup on, fasten three of the handles onto their respective pieces of wood. The handles should align so that the bag is open above the frame--do not cross the handles. Leave one handle detached so it is easier to light the candles.

When you are ready to fly your balloon, make sure you are in an open area outside, clear of branches, roofs, or power lines. With an assistant holding the bag above the candles, carefully strike a match and light the candles while holding the unattached handle away from the flame. Once the candles are lit, tape the remaining handle to the last balsa wood strip, making sure that the bag is kept clear of the flame. It will take some time to heat the air within the bag, so be patient, and you'll be rewarded with a beautiful hot air balloon kite! You can also light it at night and enjoy your floating lantern!