Up and Away!
Problem: Why do certain gases allow a balloon to rise?
Materials: 5 sheets of tissue paper (20" x 30"), 1 standard-size
manila file folder, 44 cm of galvanized steel wire, a cotton ball, metric
ruler, rubber cement, cellophane tape, Scissors, pencil.
- Cut a large tissue paper square 50cm on a side. This will be the
top of the balloon. Then cut a small 1cm square from each of its corners.
This allows you to make a 1cm x 48cm glue flap on each edge of the
square top. These flaps will be glued to the top edges of the sides
in step 8.
- Cut rectangular pieces of tissue paper that measure 76cm x 49cm.
Then cut off two triangular pieces 30cm x 14cm from one end.
- Mark a 1cm wide glue flap along four of the edges of each side.
- Cut three corner notches on each side.
- Make the bottom of your balloon by cutting two 20cm squares from
a manila folder. Then cut out their centers, leaving 1.5cm frames.
Put a thin layer of rubber cement on one side of each frame. When
the cement has completely dried, touch the cemented surfaces together
and they will bond instantly. This method of gluing surfaces with
rubber cement forms the strongest bond.
- Punch a small hole in the center of each side of the frame. These
are where the two steel wires which hold the cotton ball will be attached.
- Cut two pieces of galvanized steel wire 22 cm long. Push each wire
through the center of a cotton ball and then attach them to the frame.
This cotton ball will become the heat source of the balloon.
- Glue the sides and top of the balloon together. Start by applying
a thin coat of the rubber cement to the surface of part of the glue
flap on side #1 and touch it to the edge of side #2 while it is still
wet. Follow the same procedure, glue #2 to #3, #3 to #4, and #2 to
the top. Next, glue each side to the top and then glue the edge of
#1 to #4
- Glue the lower edges of the sides together and then glue the bottoms
of the sides to the manila frame.
- To launch your balloon, gently open it up so it fills with air.
With the help of a partner, hold it in an upright position and ask
your teacher to add the alcohol fuel to the cotton and light it. As
alcohol burns up, it will slowly fill the balloon with hot gases (air),
causing the total mass of the balloon (the internal gases and fuel)
to decrease. The balloon will begin to rise out of your hands because
the cooler, heavier air around the balloon will push it up. Let go!
Your balloon will fly very high it you built it well and the atmospheric
conditions are just right.
- How do pressure and volume of a gas relate?
- What effect does an increase in temperature have on a gases Volume
- What is Charles' Law?
- What is the difference between a compound and an element?
- What is an atom?
by: The Online Teacher Resource (www.teach-nology.com)
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