Hot Air Balloons (Kevin Dixon)
Title:
Speed-Ballooning (Hot Air Balloons in 15 minutes or less!)
A Variation on Dr. Norman Herr’s Hot Air Balloon Demonstration 5.1.4 in
Hands-On Chemistry Activities with Real-Life Application
Principle(s) Investigated:
- Density
- Buoyancy
- Charles' Law
- Archimedes' Principle
- Kinetic Molecular theory of Gases
- Chemistry Standard 4c: Students know how to apply the gas laws to relations between the pressure, temperature, and volume of any amount of an ideal gas or any mixture of ideal gases.
- Grade Eight 8a: Students know density is mass per unit volume.
- Grade Eight 8b: Students know how to calculate the density of substances (regular and irregular solids and liquids) from measurements of mass and volume.
- Grade Eight 8c: Students know the buoyant force on an object in a fluid is an upward force equal to the weight of the fluid the object has displaced.
- Grade Eight 8d: Students know how to predict whether an object will float or sink.
Materials:
- Dry Cleaners bags (obtained for free from a kind, local Dry Cleaning establishment)
- Ordinary copy paper
- Glue Sticks
- Hair Drier (or industrial heat-shrink gun)
Slideshow:
Procedure:
(See Slideshow above)
Student Prior Knowledge:
This is an excellent kick-off activity to introduce the unit on Gases and Gas Laws. Alternatively, one could put it at the end of this unit and add appropriate Gas Law questions.
Explanation: Give a thorough explanation of the experiment or demonstration. Your explanation should be written to give your fellow teachers a solid understanding and include greater detail than what you might provide for your secondary students. Make certain to include equations whenever pertinent.
Questions & Answers:
- Why does the balloon rise?
- Would it rise faster or slower on a colder day? Why?
- Compare and contrast this hot air balloon with the helium balloon you see at parties.
Applications to Everyday Life:
- Buoyancy (the force created by displacing a fluid of greater weight) explains why ships float as well as why balloons rise.
- Thermal differences in the same fluid mass explains weather phenomena such as inversion layers and thunderheads.
- Air-filled balloons are a very powerful tool in the work of underwater excavation and salvage. The weight difference between a gas and the liquid water surrounding it creates a powerful force.
Photographs:
(Also see Slideshow above for photos of HS Students making and flying tissue paper balloons)
Lesson:
Videos:
Tissue Paper Balloon Construction and Flight
Computer Simulation:
References:
- Herr, N., & Cunningham, J. (1999). Hands-On Chemistry Activities with Real-Life Applications. San Francisco: Jossey-Bass.