To demonstrate how several stages of of a rocket can operate in steps
to propel a rocket.
Two inflated balloons are joined in a way simulate a multistage rocket
launch as they slide along a fishing line on the thrust produced by escaping
Gregory Vogt, OSU
Roger Storm, NASA Glenn Research Center
- 2 long party balloons
(round balloon will not work)
- Nylon monofilament
fishing line (any weight)
- 2 Plastic straws
(milkshake size, non-bendable)
- Styrofoam cup
- Masking tape
- Thread the fishing
line through the two straws. Stretch the fishing line snugly across
a room and secure its ends. Make sure the line is just high enough for
people to pass safely underneath.
- Cut the cup in
half so that the lip of the cup forms a continuous ring.
- Loosen the balloons
by preinflating them. Inflate the first balloon about 3/4 full of air
and squeeze its nozzle tight. Pull the nozzle through the ring. While
someone assists you, inflate the second balloon. The front end of the
second balloon should extend through the ring a short distance. As the
second balloon inflates it will press against the nozzle of the first
balloon and take over the job of holding it shut. it may take a bit
of practice to achieve this.
- Take the balloons
to one end of the fishing line and tape each balloon to a straw. The
balloons should be pointed along the length of the fishing line.
- If you wish, do
a rocket countdown and release the second balloon you inflated. The
escaping gas will propel both balloons along the fishing line. When
the first balloon released runs out of air, it will release the other
balloon to continue the trip.
Travel into outer
space takes enormous amounts of energy. Much of that energy is used to
lift rocket propellants that will be used for later phases of the rocket's
flight. To eliminate the technological problems and cost of building giant
one-piece rockets to reach outer space, NASA, as well as all other space
fairing nations of the world have chosen to use a rocket technique that
was invented by 16th-century fireworks maker Johann Schmidlap. To reach
higher altitudes with his aerial displays, Schmidlap attached smaller
rockets to the top of larger ones. When the larger rockets were exhausted,
the smaller rocket climbed to even higher altitudes. Schmidlap called
his invention a "step rocket."
NASA utilizes Schmidlap's
invention through "multi staging." A large first stage rocket carries
the smaller upper stages for the first minute or two of flight. When the
first stage is exhausted, it is released to return to the Earth. In doing
so, the upper stages are much more efficient and are able to reach much
higher attitudes than they would have been able to do simply because they
do not have to carry the expired engines and empty propellant tanks that
make up the first stage. Space rockets are often designed with three or
four stages that each fire in turn to send a payload into orbit.
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