NC Essential Standards Alignment:
Grade 6, 7, and 8: Goals 1 and 2; High School Physics
7.P.1, 7.P.2, Phy.1.1, Phy.1.2, Phy.1.3, PSc.1.1, PSc.1.2
See the National rules manual
Event Score Sheet:
National Event Page:
Teams must bring safety spectacles with side shields and the tower.
Event Leaders will provide all measuring and testing apparatus
This is a building event. Teams will design and build ahead of time a tower constructed from wood and glue capable of bearing a load. The official rules define the minimum/maximum dimensions that the tower must have. At the competition teams will place their tower on the testing platform, and load sand into a bucket suspended and supported by the tower. The tower will be loaded until either the tower breaks or 15 kg is held, whichever occurs first.
High score wins. Scoring for this event is based on efficiency. There is an added base bonus this year. The following formula will be used:
(Load supported + load score bonus)/Mass of Tower
Towers that fail to meet one or more of the requirements will be ranked in a 2nd tier beneath those that do meet requirements. Towers that cannot be tested at all will be ranked in a 4th tier below those that can be tested. Ties will be broken first by whichever tower is lightest, then by whichever tower is tallest.
The goal is not to build the strongest tower, it is to build the most efficient tower. Most winning towers will break before hitting 15kg
students will also have to estimate what their load supported will be this year. This number will be used only in tie breaker situations.
From the National FAQs page:
(Section: 6 / Paragraph: c / Line: 2)Yes, the tower must hold the bucket to earn the bonus. Teams will not receive the Load Score Bonus (6.c.) if their Tower breaks prior to loading sand which is defined as sand being added to the bucket either by pulling the lever of the hopper or the participants attempting to pour sand into the bucket. These teams will have the mass of the Loading Block Assembly used as their Load Score (6.b.) for the purposes of determining the final event score (6.a.).
(Section: 6 / Paragraph: B / Sub-Paragraph: I / Line: 1)02/08/2018The minimum load scored is that of the Loading Block Assembly (6.b, 5.b). So if a tower cannot support the Loading Block Assembly it must be scored in Tier 4; unable to be loaded. If the tower supports only the Loading Block Assembly, then the tower is scored in the appropriate tier (1, 2, 3) and the weight of the Loading Block Assembly is scored.
Be careful when constructing your tower that it is level. If the base or any part of the tower is leaning or crooked, it will lean even more as weight is applied and potentially tip over before it breaks, as this one does.
The process of placing your tower on the platform, threading the chain through, hanging the bucket, and how to load the sand. This is the PVC “breaker” used throughout NC.
A tower supports 15 kg before breaking. This or a very similar apparatus is the sand loading device (breaker) used at every NC regional and state tournament. A lever on the back releases sand at a rate of the competitor’s choosing, which flows down a chute into the 5 gallon bucket. The bucket handle has been replaced with a rope, so the bucket will self- center and all the weight is always in line with the chain.
Instructional video for how to glue balsa for your tower and what kind of glue to use.
How to attach the sides of your tower base at the proper angle.
Simply placing your tower diagonally across the platform opening reduces the length of the sides needed, thus reducing the tower weight and increasing your structural efficiency.