Virginia Science Olympiad:
Bottle rocket and towers
Bottle Rocket: Adapted from the NC
presentation by Mark & Grant Wylie
Towers : Courtesy Leah Puhlick, Langley HS
coach
BASICS TO REMEMBER
 Each device should be clearly labeled with
the team name and number
 Note: All building events with the
exception of Bottle Rocket must be
impounded
 Any student on the team may help build,
impound, and/or compete with the device
 FOLLOW THE RULES!
SAFETY REGULATIONS
 Under each event description there is a section for “eye
protection” followed by a number
 Descriptions of what these numbers refer to appear on
the www.soinc.org under “events”
 For Bottle Rocket - # 5 or high impact goggles/spectacles
must be worn – that is they must be rated ANSI Z87+
 For Towers - #2 Safety Spectacles with Side
Shields ANSI Z87
BOTTLE ROCKET
 Teams of 2 students
design, build, and
bring bottle rockets for
maximum flight times
 Longest flight wins; 2nd
flight is used as tie
breaker
 Tier 2 - launch with
rocket parts separating
during launch or flight
 Tie 3 - construction
and/or competition
violations
Important Rules
 Build as many rockets as you like but have 2 ready
for the tournament with no metal or
commercial bits. Unaltered pressure
chamber and safe nose.
 MUST WEAR SAFTRY GLASSES
 Nothing within 5 cm of the nozzle (Fins and other
parts must be 5 cm or higher above the opening of
the bottle)
 What goes up must come down SAFELY
More Rules…
 Rockets will use 2 liter soda bottles
 Labels may be removed from the bottle but
MUST be presented at safety inspection
 Launched at 75 psi
 Best single rocket time will win
 Ties resolved by the flight time of the second
rocket
How does it work…
 Water is poured into the pressure chamber
 Air is then pumped into the bottle.
 When the rocket is released, the air forces the
water out of the bottle.
 Newton’s Third Law of Motion kicks in - for
every action there is an equal and opposite reaction
 the rocket's action is to push down on the ground
with the force of the pressurized air that is pumped
in, and the reaction is that the ground pushes the
rocket upwards with an equal force.
Parts of the Rocket and Forces
Pressure Chamber
 2 Litter soda bottle
 Do not cut or scratch the pressure chamber.
 Can glue fins to pressure chamber with silicone or
polyurethane glues or simply use strong packing
tape.
 If pressure chamber is damaged it will not be
launched
Fin Shapes
Recovery Systems
 A recovery system is something that slows the
rockets decent.
 The two most popular at the parachute and the
back-slider
ONLY A BACK-SLIDER IS ALLOWED IN THIS
YEARS RULES
Launcher
 Commercial Bottle Rocket Launcher: about $200
http://shop.pitsco.com/store/detail.aspx?KeyWords=
rocket+launcher&searchtype=0&sport=3&by=20&c
=0&t=0&l=0&ID=1179
 Build one – MUCH more affordable
http://faculty.kfupm.edu.sa/AE/aymanma/images/H
ow%20to%20make%20a%20sodabottle%20rocket%20launcher.pdf
Resources
 http://dogrocket.home.mindspring.com/WaterRockets/




center of gravity & center of pressure
http://waterrocket.uh-lab.de/backglide.htm backslider
construction and discussion
http://txsnapper.eezway.org/powerdeployment/ great
info Robert Youens -Coney
http://www.info-central.org/index.php?article=276
cg.cp.cla
http://www.scioly.org/wiki/Main_Page SO student
center
http://en.wikipedia.org/wiki/Water_rocket General good
Towers
 Students design a
tower with best
efficiency
 up to 15 kg of mass
will be tested
 impounded
Towers - basics
 Important measurements:
Must
be a min. of 50 cm above test
base
Must span 20x20 cm opening on test
base
Must pass through 8 cm diameter
hole 30 cm above test base
Towers basics
Towers - basics
 Other things to note:
 Must
be wood and glue (no bamboo,
laminates, etc.)
 No maximum wood size
 Must support 5x5x2 cm block w/ ¼ “
threaded rod 50 cm above test base
 Chain must hang within 2.5 cm of center
of test base when bucket attached
Towers - scoring
The score is pure efficiency:
Efficiency = (mass held)2
bridge mass
 Bridges that don’t meet specs are tested but moved
to tier 2
 Bridges that are untestable are in tier 3 and ranked
by mass
Towers - tips
 Balsa has best weight to strength ratio – order
online for better pieces
(http://www.modernss.com/ has good balsa,
cutters, etc.)
 Glue adds the most weight – use sparingly
 Have students draw plans, cover with clear
packing tape and work on top of plan
 Keep everything symmetrical, level, square