NSF GK-12 Graduate Fellows Program
Award # DGE-0139171
University of North Carolina at Wilmington
Hot Air Balloon Activity Notes
Activity Instructions
by
Jeff Marshall, Department of Earth Sciences
Activity aligned with the 2001 North Carolina Standard Course of Study for 7th Grade Science: Goal # 1
Hot Air Balloon Activity Notes
Goals: This activity can be aligned with Goal 1 (atmosphere) for Grade 7, as well
as Goal 4 (matter). Several topics tie into or lead up to the construction and
launching of balloons including:
• Gas Laws
• Air Pressure
• Atmospheric Composition and Structure
• Wind Speed and Direction
• Inversions
• Weather Prediction (i.e. weather balloons)
• Technological Advances in Science
Premise: Hot air is lighter (or more appropriately less dense) than cold air.
Balloons filled with hot air rise because they have less mass per unit volume than
the air around them. The balloon is pushed up by the cooler air around it. A
balloon floating free in the air senses no wind and no air forces except the dynamic
effects of turbulence; it rides with the wind as part of the air mass. Obviously there
is much more to this, but you get the idea.
Several websites do a great job outlining the construction and launching of
balloons. Here are a couple of them and if you don’t like these do a google search
to find more:
http://www.juniorballoonist.com/
http://www.solo.wustl.edu/SoloSpirit2/education/Ballooning/makeone.html
http://www.kyrene.k12.az.us/schools/Pueblo/Tech/hotairballoons.htm
http://www.kbears.com/balloon.htm
http://travel.howstuffworks.com/hot-air-balloon7.htm
http://etc.sccoe.k12.ca.us/i2001/lgsballn.html (.mpeg movie on launch)
Materials Tips:
• Materials outlined by the websites all work well. Some smaller scale
projects say to use dry cleaning bags but they are lack color, require no true
construction and in my opinion are lame.
• For a class of 100 students our costs exceeded $90. Luckily we begged,
borrowed, and pilfered from other classrooms and there was some money
left in the budget to cover our costs.
• We used pipe cleaners to stabilize our bases. Wire works well too, but is
potentially a little bit more prone to poking and tearing the tissue paper.
Construction Tips:
• Make sure you have plenty of time and emphasize to the kids to have
patience. We had only limited materials and could not afford to let students
start over and over.
• Construction took 3 days in our 90 minute classes and at least double that in
our 45 minute classes.
• Students were given index cards and a paper clip to write their names on so
as to not lose or mix their materials with other students.
• Find a place in the classroom were materials will not be disturbed. The
balloons are extremely delicate and are not meant to last. Although, rips
and tears are inevitable this will help limit them from happening.
• We modified the pattern from the www.juniorballoonist.com page such that
the original pattern fit on some poster paper we had laying around in the
classroom. I believe their pattern calls for a 50” tall balloon and ours was
38” tall. I wouldn’t go any smaller than this as it would limit the “wow”
factor and our balloons started looking like big pumpkins instead of
balloons. Looking back we had enough materials and should not have
changed the pattern.
• How much glue to use and how much overlap was a huge debate amongst
our students. 3/8– ½” worked best. As for the glue, whatever it takes to
make a good seal is my only advice.
• When lining up your pattern pieces, line up the bottoms. It’s likely that your
tops will not all meet flush and you will be covering it with a crown anyway.
Concentrate on making a nice secure base first.
• When gluing the seams we made 3/8 – ½” cuts in the piece that was to be
folded over and pasted. This just cut the seam into sections and made it
easier for the kids to work with. Four or five cuts will do it.
• Periodically take a break and let the pieces dry. Also check to see if
opposing pieces are accidentally being glued together or worse, to the table
you are working on.
• After construction and before putting the crown on, allow students to blow
up their balloons with cold air from a hair dryer to search for potential leaks.
This way they can fix ‘em before the big launch.
Launching
• If you are launching outside, choose the best atmospheric conditions
possible. Cool to cold mornings with light and variable winds are ideal.
Keep an eye out for power lines and trees...some of the balloons went pretty
far.
• We were fortunate enough to have an apparatus already built by out
technology teacher that utilized a propane burner attached to a long pipe.
This thing worked awesome. See the pictures below.
• If you have to launch inside, get permission to use the gym or cafeteria.
• Of course, keep the kids away from the hot stuff. Put ‘em to work by
marking off distances the balloons traveled and timing the duration the
balloon was aloft.
• Take plenty of pictures and invite other classes to come see the launch as
well as local media. And remember…have fun!
Construction Pictures:
Launching Apparatus