Hot Air Balloon Model

Jack Schumacher

To recreate our balloon you will need to follow these guidelines:

Supplies:

• pliers/wire cutters and scissors

• one 30 gallon black trash bag (be sure it is as thin as possible)

• 4 pieces of aluminum wire (2x 16 inches) and (1x 3 inches) and (1x 5 inches)

• 2 strings (each 14 inch sections)

• 4 replaceable metal sided candles

• 1 metal container that can hold at least 1 cup

• masking tape

• tinfoil (1 inch x 3 inch)

• Propane burner or any other burner safe for your environment.

Instructions:

1. Scrape the wax from the 4 replaceable metal candles into the metal container (make sure to remove the wicks you can throw them away)

2. Turn on the burner and place the cup of wax over it close enough to melt the wax inside in a reasonable time

3. Wait for the wax to melt

4. Once the wax is melted turn the burner down or off (note: if you turn the burner off the wax may harden and you will need to reheat it and melt it again to coplete the next step)

5. While the wax is melted and is in liquid form grab one end of the string and dip 14 inches of it in the wax for 3-5 seconds

6. Raise the now wax soaked string out of the wax and continue to hold the string over the metal container until the wax on the string has dried.

7. Repeat steps 5-6 for the second string

8. Once both strings are dry

9. Cut the 2 inches that are not soaked in wax on each string

10. Next set cut each string into 7 inch sections you should have 4 pieces of string that are 7 inches long

11. Cut all 4 pieces of string into 3.5 inch sections when done you should have 8 pieces of string

12. take the 8 pieces of string and put them together lined up

13. Once the string is put together take the 1x3 tinfoil and wrap it around the bottom half of the string. CLICK HERE to see what this should look like completed.

14. Once that is done take the 3 inch wire and wrap it around the aluminum foil make sure it is wrapped tightly then take the pliers and pinch the wire so that is tightly attacked to the tinfoil bundle of string . CLICK HERE to see what this should look like completed.

15. Then take the 5 inch wire and wrap it around starting from the middle and wrapping each side to the other side of the bundle once (this piece gives us the ability to attach it to the rest of the balloon. CLICK HERE to see what this should look like completed.

16. then set the bundle aside

17. Take the 2 16 inch wires and wrap one around the other in the middle of it then wrap the other one around the last one. CLICK HERE to see what this should look like completed.

18. Next grab the bundle and the wire x you just made and wrap one of the wires coming off the bundle to one side of the x within .25 inches of the middle of the x then wrap the other one around the opposite side of the x again at least within .25 inches of the middle. CLICK HERE to see what this should look like completed.

19. Bend .5 inch of the ends of the wires up toward the top of the wax soaked strings

20. Grab the 30 gallon bag and open it up so that it is full of air

21. grab four 1 inch sections of masking tape and tape each bent up pieces of wire equally distant from each other inside the bag no farther than 1 inch up from the opening of the bag

Directions for Flight

1. Have one person gold open the bag so that the walls are as far from the soaked strings as possible.

2. Light the top of the strings with a lighter

3. Continue to hold the bag up and open until the balloon begins to lift or supports the bag itself.

4. You are done you have achieved flight with your very own hot air balloon

Reasoning

When making our balloon we were trying to reduce the weight by as much as possible because based on our data the balloon could only lift 23.2 grams of mass and the mass of our balloon is 24.4 grams witch lead us to believe that the balloon should have not floated. but this is okay because due to a limitation in our data collection we were not able to see that the wax soaked candles added a significant amount of weight to our balloon and that as they burned down they lost a significant amount of mass decreasing the total mass of the balloon below 23.2 grams allowing it to rise up. In this situation the lifting force is determined by the difference of the density of the air inside the balloon to the density of the air outside the balloon. We made this realization when we weighed the balloon afterward and it weighed only 22.8 grams after all the wax and string had burned off, this lead us to make a logical conclusion that as the wax burned off the balloon lost overall weight allowing it to lift.

Limitations

How did the balloon lift even though data suggest it wouldn't?

One limitation is that our data shows that our balloon can lift 23.2 grams and its mass is 24.4 grams leading us to believe that it will barely lift off the ground at the most. This is not the case though this design allowed for our balloon to lift fairly quick. This lead us to ask ourselves why and how this happened the data predicted so differently. We ultimately concluded that the temperatures we used for our calculations were incorrect and the uncertainty from the original temperatures were as follows outside was 2-5C positive or negative and for inside 10-20 in the positive direction . We made this conclusion because we ruled out uncertainty in all of our other data points and these were the only ones that were estimates . This makes sense because if the temperature of the air outside the balloon just was 5C less than what we used to make our calculations it brings the mass that the balloon can lift up to 25.6 grams. With this new data in mind we had answers to our questions because we now know that our balloon did have the ability to lift. If you raise the temperature inside the balloon for calculations the mass the balloon is able to lift goes up to 29.2 grams, and if you include both new numbers in the calculation the lift goes up to 31.6 grams. This new data answers our previous questions because it significantly raises the balloons lifting force to an amount that lifts our uncertainty about the balloons ability too lift.

Our Data

Temperature of the air in a balloon: 80C

Temperature of the air outside the balloon: 20C

volume inside of the balloon : 113562.3 CM cubed or 30 gallons

mass of the air inside the balloon: 113.5623g

Density: 0.001

Lifting Force: 0.227 (N), 0.0232 (kg), 0.051 (lb)

mass of hot air balloon: 24.95(g)

To calculate our lifting force we used THIS website and input the data collected in the following steps:

we did this first by finding out that our bag was a 30 gallon bag and a quick google search converted that to 0.113562 meters cubed and entered it into the website.