Lesson Title: Lighter Than Air: Building a Hot Air Balloon
Grade Level(s): 3-8
Timeline: 3-4 Days
Lesson Overview: In this activity, students work in teams to construct a hot air balloon out of tissue paper to demonstrate how a hot air balloon flies. They will develop a conceptual model to explain why the balloon rises when heated.
- Students will build a working model of a hot air balloon.
- Students will understand the concept that hot air is lighter than cool air, because it has less mass per unit of volume.
- Students will be able to model lighter than air flight.
- Students will be able to describe the difference between hot air balloons and gas balloons.
MSETS14. Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.
MSPS14. Develop a model that predicts and describes changes in particle motion, temperature, and state of a pure substance when thermal energy is added or removed.
Crosscutting Concepts: Cause and Effect, Energy and Matter, Structure and Function
Science and Engineering Practices: Developing and Using Models, Constructing Explanations and Designing Solutions
- Tissue Paper (20” X 30”) 21 sheets per balloon
- Glue Sticks
- Cardstock (1 1/2 inch strips enough to make a 10” diameter ring)
- Hot Air Gun
Density: The measure of how much matter is in a certain volume.
Fluid: Asubstance that has no fixed shape and yields easily to external pressure; a gas or a liquid.
Pressure: The continuous physical force exerted on or against an object by something in contact with it.
Gravity: The force that attracts a body toward the center of the earth.
Gore: A sector of a curved surface.
Day 1-2: Build
- Create the template. This can be done in advance to save time.
- Print out the template PDF and tape together, cut along the curved line.
- The template is for half of the gore (each individual piece is called a gore). You will need to fold a piece of butcher paper in half, trace the gore, cut, and unfold it. Do not cut along the fold.
- Transfer the template to cardboard or foam board. (Optional: This is helpful if building multiple balloons.)
- Build the tissue paper panels.
- Overlap sheets of tissue paper by 1 inch and glue together using a glue stick.
- You will need 3 sheets of tissue paper per panel.
- You will need 7 total panels.
- Stack the 7 panels on top of each other.
- Lay the template on top of the panel stack and cut all 7 layers at once.
- Select 2 gores and lay them on top of each other.
- Leave a 1/2 inch margin to the right so gore #2 shows. (Diagram 1)
- Apply a line of glue along the 1/2 inch margin of the bottom gore. (Diagram 2)
- Fold the bottom gore onto the top gore. (Diagram 3)
- Place gore 3 on top of gores 1 and 2 leaving a 1/2 inch margin on the left.
- Apply a solid line of glue along the 1/2 inch margin of gore 2.
- Fold gore 2 onto gore 3.
- Repeat this process for the remaining 4 gores.
- Join the free edges of gore 1 and gore 7. This will create a circle when opened.
- Hint: As you glue be sure to occasionally make sure the folds are not sticking together.
- Tie the top of the balloon together using string or ribbon, 1/2 1 inch from the top.
- Using cardstock and staples create a 10 inch ring.
- Place the ring inside the mouth of the balloon, loop the tissue paper around the cardstock ring, and staple.
- Hint:You may have to fold the tissue paper together to make it fit snugly around the ring.
- Let the balloon dry completely before launching.
- Patch any holes or rips in the balloon by gluing left over tissue paper over the opening.
- If launching in a place with limited space, you can attach a tether by stapling string to the inside of the ring and securing the other end to the floor.
Day 3: Launch
- With 2 or 3 people, gently pick up balloon and begin to pull folds out to shape the balloon.
- Hold the bottom of the balloon over a heat gun.
- Turn on the heat gun and allow the balloon to fill up and take shape.
- Start with cool air if available.
- Discussion Question: Why isn’t the balloon flying?
- Turn on the hot air.
- Discussion Question: Why does the balloon fly now?
- WARNING: Heat guns get very hot, use caution when holding the balloon.
- As the balloon begins to pull upward, release and enjoy the flight.
- WARNING: Do NOT launch in the vicinity of power lines!!!
- Have students create diagrams showing what is happening to the air inside the balloon and why it is flying.
- Why did the hot air balloon float?
- What was happening to the air molecules inside the balloon?
- How could we improve the design of our hot air balloon?
- Using your knowledge of how a hot air balloon flies, can you make a guess about how helium balloons float?
- What would be some advantages or disadvantages to flying in a hot air balloon?
- Why might the hot air balloon be shaped long and narrow, rather than round like a birthday balloon?
- Design a basket to carry weights and have students compete to see whose balloon lifts the most.
- Compare the lifting capacity of your hot air balloon to helium balloons.
- How Stuff Works - Hot Air Balloons
- Hot Air Balloon Gore Template