because our hot-air balloon must end up being lighter than the air displaces were going to weigh all of our components start by cutting a square of aluminum foil about four inches square which is about ten centimeters square the lumen square weighs about two tenths of a gram stick on candles in four places an inch or about twenty-five millimeters from the edge all four candles weigh about five and a half grams so far the best way we found to stick the candles to the file is by sticking the aluminum over the edge melting the bottom of the candle a little then heating it from below the aluminum then slide is the aluminum back onto the table press down and hold the candle very still as the wax solidifies as you can see it takes practice and the candle will snap off if they get bumped the bigger pool of wax that sticks on the candle the stronger the candle is against being knocked off next make the rigid X that holds the balloon open if you gently stretch the opening of the balloon and measure this dimension you can calculate how long the sticks that make up the X should be multiplied the dimension by 0.7 so with the bags we use the measurement is about 57 centimeters so multiplied by 0.7 we get about 40 centimeters cut off the bendy part of the straw if that is what kind of straw you are using and keep the long stiff part of the straw you will need to tape several together we find that the connections are a little stronger if we make two short cuts in the end of one so there's a bit of overlap find the middle of each and tape together the X tape the ends of one stick onto the opposite points of the bag then tape the ends of the other stick all six straws we need for the X way less than two grams keep the aluminum platform on top of the straws so when the candles burn down they will not melt the straws tape the corners to the straws the candle should not be directly above the straws they should be offset so they don't melt the straws if though balloon will fly outta reach tie thread to the cross of the X the aluminum squares make the hot air balloon housebroken so it doesn't drop wax and you can reuse the balloon indefinitely just by attaching new candles again there's enough letter in the world already people assume that even small hot air balloons must be flown outdoors however even a slight breeze is too much to fly a hot air balloon in most of the time it's better to fly it inside and very hot weather the balloon will lift a little less efficiently than in cold weather although it is possible for one person to launch it it's easier if one person holds the bag from the top while the other person lights the candles it's still a challenge to have to look from below and have to reach up into the loop it might be a little easier if you use a candle instead of a lighter be careful to keep the flame away from the plastic it will take a minute or two to heat the air sufficiently if you have trouble getting the balloon up you can reduce the old weight by cutting the candles in half