SECME Water Rocket Design Competition

Patch Design

• Creative display• Reflects the dedication

and mission of the team• Has a :– Symbolic Picture– Team’s name– SECME Theme for Year

STS-103 -Hubble Space Telescope Repair

STS-106 - Flight to International Space Station

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 ConeNose Cone• 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 FinsFins• 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• 2, 2-Liter Plastic Soda Bottles• Newspaper or other material (Ballast)• Foam Tray or other material (Fins)• Poster board (Nose Cone)• 1.5 inch Styrofoam Ball or other material (Nose

Cone)• Clear Packing Tape, Glue (adhesives)• Scissors• Marker• Ruler

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