SECME Water Rocket Design
Competition
Patch Design
• Creative display
• Reflects the dedication
and mission of the team
• Has a :
STS-103 Hubble Space
Telescope
Repair
STS-106 - Flight
to International
Space Station
– Symbolic Picture
– Team’s name
– SECME Theme for Year
Apollo 11 - Land
on the surface
of the Moon
STS = Space Transportation System
What is a Water Rocket?
• A water rocket is a chamber (2-liter plastic soda
bottle) partially filled with water.
• Air is forced inside with a pump.
• When the rocket is released, the pressurized air
forces water out of the nozzle (pour spout) and the
rocket launches into the air.
Water Rockets- Questions to Think
About
• Do I have to use water?
Why can’t I just use
pressurized air?
• How can I modify the
design of the rocket to
increase the duration
of the flight?
• How will wind affect
the rocket after it is
launched?
Propulsion-Thrust
• Propulsion – a force that
pushes or drives forward
• Thrust - the forward force
produced by the gases
forced from a rocket
• Launch=thrust greater
than weight (thrust will
make the object
accelerate upwards)
• For every action there is
an equal and opposite
reaction (Newton’s Third
Law of Motion)
• Can you now think of why
expelling water might be
better than expelling just
air?
• Water is heavier than air
because it is DENSER. This
means that more water
molecules are packed into
a given volume.
Stability & the Nose Cone
Nose Cone
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Key Point: Stability increases as the
distance between the Centre of Mass
and the Centre of Pressure increases
Nose cone adds weight to the top of the
rocket
The Centre of Mass of an object is the
point at which all of the mass of an
object can be thought to be
concentrated
Center of Gravity (Centre of Mass)
balance point, moves forward
The first point that meets the air is the
nose cone at the front end of the rocket.
If the speed of a rocket is less than the
speed of sound (1200 km/h in air at sea
level), the best shape of a nose cone is a
rounded curve.
Nose cone reduces drag
Stability & the Fins
Fins
• Fins add stability
• Fins helps control direction
• Counteracts sideways motion of the rocket
• Air flows smoothly past them if the rocket is
traveling along its axis
• If there is sideways motion, then the air
striking the fins pushes the rocket back
towards straight motion
• Placing fins at the tail end of a rocket (behind
Centre of Gravity) moves the centre of
pressure closer towards the tail end and
increases stability. However, this also
increases drag, so there is an optimal size for
fins so that the rocket has enough stability
without having too much drag.
• Stiff fins are best-flexibility decreases
effectiveness
• Recommendation: 4 fins, equidistance apart
Materials
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2, 2-Liter Plastic Soda Bottles
Newspaper or other material (Ballast)
Foam Tray or other material (Fins)
Cardstock Paper (Nose Cone)
1.5 inch Styrofoam Ball or other material (Nose
Cone)
Clear Packing Tape, Glue (adhesives)
Scissors
Marker
Rules
Parts of the Water Rocket
• Nose Cone – for
aerodynamic effect/shape
can help to reduce drag
• Ballast – adds mass to
rocket to increase stability
(*stability is the single most
important factor in rocket
design-helps rocket go
higher)
• Fins – for aerodynamic
effect/shape can increase
stability
• Pressure Vessel – source of
rocket propulsion