Join us for a rocket showdown to see who can fly the farthest!

Build a rocket, show up, and Mr. Darlington's physics classes will supply the launcher, the rocket fuel (compressed air and water), and tell you how far your rocket can fly.

Launch distances will be on twitter:

www.twitter.com/galwayphysics

Two-liter bottle , top-heavy, two-fifty grams three fins, tough

Building a simple rocket is cheap and easy. You probably have everything you need already. These instructions are only a suggestion, and you csn use materials other than what is listed below as long as the body of our rocket is a 2-liter bottle as described below.

TWO LITER BOTTLE
IMPORTANT! Bottles must have a 'regular' sized flange. Some bottle manufactures make bottles with oversized flanges - THESE WILL NOT FIT THE LAUNCHER! If you compare a few brands on the shelf, you'll notice the larger sized flange - don't buy it, get the 'standard' size. Other than this stipulation, any two liter will do.

TOP HEAVY
High flyers will have most of the rocket mass concentrated as close to the tip of the nose cone as possible. Moreover, if the nose cone isn't balanced, the rocket will hook and not fly straight. CAUTION: Do not use anything for mass that could be projected as shrapnel in the event that a rocket bursts on the launcher. Screws, nails, rocks, marbles, pebbles, nuts, bolts will not be permitted. Use innocuous building materials such as clay or play-dough.

TWO HUNDRED AND FIFTY GRAMS - just over half a pound
The ideal rocket is not too heavy and not too light - around 250 grams is just right.

TOUGH
Rockets have been known to travel well over 100 meters at speeds of 50 meters per second. They must be durable to survive multiple launches. Many rockets have had an early exit from competition because they didn't hold up.

THREE FINS
While three is the ideal number, rockets with four have also done well. Make fins, not wings. Smaller fins are better. Place them towards the back of the fuselage, pointed away from the bottle opening where the fuel comes out.

A good rocket flies like an arrow, not an airplane. Fins go on at the back where the water leaves for stability, and most of
the rocket’s weight must be on the front - in the nose cone - to balance the exiting air and water. Successful rockets fly
balanced - completely frozen in the air. Balance and stability become more of a factor as launch pressures increase. An unbalanced rocket might fly reasonably well at lower pressures (40-50 psi), but weaknesses and stability issues may emerge at higher pressures (100+ psi).