Hot Air Balloon Heights

based on 104 ratings
Author: Josh M.



To find out if i made a hot air balloon with a toaster as a heat source and a bag for the balloon, would a bigger bag go higher than a smaller bag?




Elementary School, Fifth Grade

Difficulty of the Project



About $5

Safety Issues

This Project is relatively safe.

Time Taken to Complete the Project

2 Days


To find out if I made a hot air balloon with a toaster as a heat source and a bag for a balloon, would a bigger bag fly higher than a smaller bag?

Materials and Equipment

  • Toaster (Heat Source)
  • 4 Plastic Bags (Each with a different measurement. I cut each one a little smaller)
    • 73.6cm
    • 63.5cm
    • 43.18cm
    • 27.94cm
  • 1 Post Board, 55.8 x 71.1cm
  • Scotch Tape
  • Yarn
  • Sticky Pads
  • Scissors
  • Tape Measure
  • Push Pin
  • Pencil
  • Marker
  • Notepad


The first hot air balloon was invented in 1782 by two brothers, Joseph and Etienne Mongolfier. They discovered that hot air was lighter than cold air. They made a small silk balloon and it elevated thirty-two meters in the air. They found out that the hotter the air, the higher the balloon rose. They two brothers promised their dad they would never fly the machine themselves, so they sent a duck, a sheep and a chicken into the air. They flew for eight minutes and the animals were still alive. The entire science academy and Louis XVI witnessed the entire event. Louis XVI allowed a man named, Pilatre Rosier, to attempt to fly with a passenger. Their flight over Paris lasted 28 minutes while both men fed a fire placed in the middle of the basket.

The discovery gave the brothers a legacy of flying balloons. A competition started up between Pilatre and the brothers to see who could fly the highest. They started making balloons bigger. Pilatre died after he tried to fly from France to England in 1785. His balloon caught fire because he had a small bag of hydrogen attached to his basket.

Research Question

When making your own hot air balloon, does a bigger bag cause the balloon to fly higher than a smaller bag?


My guess is, the bigger the hot air balloon, the higher the balloon will go.

Experimental Procedure

  1. I put a piece of tape on a piece of yarn and placed the push pin into the tape and had my dad get on a ladder and put the push pin into the highest point in our ceiling, so the yarn was hanging from the ceiling.
  2. I taped the end of the yarn to the floor and marked one meter increments all the way up the yarn with a piece of tape.
  3. I cut the poster board in half and taped it together to form a circular shape, making sure it fit tightly around the toaster.
  4. I cut a little bit off of each bad except one. The first bag, I cut about 10 cm off, the second 30cm off, and the third about 45 cm off.
  5. I plugged the toaster into the wall by the measured yarn.
  6. Finally, I was ready to complete the experiment. I tested each size bag, placing each bag over the circular poster board.
  7. Turned the toaster on (each time at the same setting in order to have just one variable).
  8. Placed the poster board with the bag attached over the toaster. Held each bag up in place, so it didn't melt.
  9. Waited for the bag to fill. Once filled, if the bag didn't go up straight, I placed sticky notes for weights on the end of the bag and tried it again until each bag went up straight 3 times each.
  10. I recorded what happened on a notepad.
Add your own comment