1. 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

2. Each device should be clearly labeled with the team name and number
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!

3. 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 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

4. 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

5. 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

6. 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

7. 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.

8. Parts of the Rocket and Forces

9. 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

10. Fin Shapes

11. 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

12. Launcher Commercial Bottle Rocket Launcher: about $200
Build one – MUCH more affordable

13. Resources
center of gravity & center of pressure
backslider construction and discussion
great info Robert Youens -Coney
cg.cp.cla
SO student center
General - good

14. Students design a tower with best efficiency
Towers
Students design a tower with best efficiency
up to 15 kg of mass will be tested
impounded

15. Important measurements: Must be a min. of 50 cm above test base
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

16. Towers - basics

17. Towers - basics Must be wood and glue (no bamboo, laminates, etc.)
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

18. The score is pure efficiency: Efficiency = (mass held)2 bridge mass
Towers - scoring
The score is pure efficiency:
Efficiency = (mass held) 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

19. Towers - tips
Balsa has best weight to strength ratio – order online for better pieces ( 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