Overview
Bungee Drop is a Division B event where teams design, build, and test a device using elastic materials to drop an egg-shaped object as close as possible to a target without breaking it. This event combines principles of physics, engineering, and experimental design to create a device that utilizes elastic potential energy.
Quick Facts
- Type: Build Event
- Format: Pre-built device with on-site testing
- Team Size: Up to 2 students
- Time Limit: 8-minute setup and testing period
- Materials Allowed: Elastic materials, device components, and log book
Rules & Format
Event Format
Bungee Drop consists of the following components:
- Device Construction: Teams build their bungee device prior to the competition
- On-site Testing: Teams drop their egg-shaped object from a specified height
- Documentation: Teams maintain a log book with design process, data, and analysis
Materials Allowed
Teams are permitted to bring:
- The pre-built bungee drop device
- Elastic materials (rubber bands, bungee cords, etc.)
- One or more egg-shaped objects (plastic eggs, ping pong balls, etc.)
- Tools for adjustments and repairs
- Log book with calculations, data, and event documentation
- Non-programmable, non-graphing calculator
Note: Event supervisors will provide the target and measuring equipment. Always check the current year's official rules for any updates or changes.
Content Guide
Bungee Drop covers various concepts in physics and engineering. Here's a breakdown of the major content areas:
Core Physics Concepts
- Elastic potential energy
- Hooke's Law and spring constants
- Gravitational potential energy
- Conservation of energy
Engineering Design
- Material selection and testing
- Structural integrity
- Load distribution
- Iterative design processes
Data Collection & Analysis
- Experimental design
- Statistical analysis
- Error analysis
- Predictive modeling
Competition Skills
- Device calibration
- Quick adjustments
- Time management
- Documentation presentation
Physics Theory
Hooke's Law
The fundamental principle behind elastic materials:
F = -kx
Where:
- F = Force exerted by the elastic material (in newtons, N)
- k = Spring constant (in N/m)
- x = Displacement from equilibrium position (in meters, m)
Elastic Potential Energy
The energy stored in stretched or compressed elastic materials:
Eelastic = ½kx²
Where:
- Eelastic = Elastic potential energy (in joules, J)
- k = Spring constant (in N/m)
- x = Displacement from equilibrium position (in meters, m)
Gravitational Potential Energy
The energy associated with an object's height above a reference point:
Egravitational = mgh
Where:
- Egravitational = Gravitational potential energy (in joules, J)
- m = Mass of the object (in kilograms, kg)
- g = Acceleration due to gravity (9.8 m/s²)
- h = Height above the reference point (in meters, m)
Energy Conservation
During the bungee drop, energy is transferred between different forms:
Einitial = Efinal
Egravitational, initial + Eelastic, initial = Egravitational, final + Eelastic, final + Ethermal
Note that some energy is lost to friction and heat (Ethermal).
Non-Linear Elasticity
Many elastic materials deviate from Hooke's Law at large extensions:
- The spring constant (k) may change with extension
- Experimental data often shows a non-linear force-extension relationship
- Multiple rubber bands or bungee cords behave differently than a single one scaled up
Materials & Design
Elastic Materials
Different elastic materials have varying properties and performance characteristics.
Common Options:
- Rubber bands (various sizes)
- Elastic cords
- Surgical tubing
- Bungee cords
Attachment Methods
How the elastic material connects to the egg-shaped object and the structure.
Considerations:
- Carabiners and hooks
- Knots and ties
- Harnesses and cradles
- Quick-release mechanisms
Support Structures
Framework that holds the bungee system in place.
Design Elements:
- Stability and balance
- Adjustable components
- Lightweight materials
- Ease of assembly
Payload Systems
How the egg-shaped object is held and protected.
Features:
- Secure containment
- Weight considerations
- Aerodynamic properties
- Impact protection
Measuring Tools
Instruments for calibration and measurement.
Useful Tools:
- Measuring tape/ruler
- Force gauges
- Digital scales
- Levels and plumb lines
Adjustment Mechanisms
Systems for fine-tuning the drop distance.
Examples:
- Length adjusters
- Tension control systems
- Quick-change components
- Modular design elements
Testing & Analysis
Experimental Design
- Controlled Variables - Maintaining consistency between tests
- Independent Variables - What you're adjusting (e.g., cord length, elastic material)
- Dependent Variables - What you're measuring (e.g., drop distance, final position)
- Replication - Performing multiple trials for statistical validity
- Systematic Testing - Methodical approach to exploring the design space
Data Collection
Important measurements and observations to record:
- Drop Height - Initial position above reference point
- Elastic Material Properties - Length, extension, force characteristics
- Payload Mass - Weight of the egg-shaped object
- Final Position - Distance from target
- Oscillation Behavior - Bounce characteristics and damping
Analytical Methods
Techniques for processing and using collected data:
- Regression Analysis - Finding mathematical relationships between variables
- Error Analysis - Calculating margins of error and precision
- Interpolation/Extrapolation - Predicting performance under new conditions
- Statistical Methods - Calculating means, standard deviations, confidence intervals
Log Book Documentation
Essential components of a well-organized log book:
- Design Process - Iterations, sketches, and decisions
- Raw Data - Tables of all measurements and observations
- Calculations - Showing work for all relevant physics formulas
- Analysis - Graphs, trends, and conclusions
- Reflection - What worked, what didn't, and future improvements
Competition Strategies
Pre-Competition Preparation
Practice Schedule
- Regular testing sessions
- Time trials to improve setup speed
- Simulated competition conditions
- Troubleshooting common issues
Device Optimization
- Fine-tuning spring constants
- Minimizing friction and energy loss
- Ensuring consistent performance
- Developing backup configurations
Log Book Development
- Organizing data systematically
- Creating clear graphs and visuals
- Including theoretical calculations
- Documenting the design process
Team Coordination
- Role assignments
- Communication protocols
- Task distribution
- Emergency procedures
Competition Day Tactics
Initial Assessment
- Evaluating competition conditions
- Checking drop heights
- Noting target position
- Adjusting for environmental factors
Quick Setup
- Efficient assembly process
- Pre-planned calibration steps
- Time-saving techniques
- Clear team communication
Strategic Drops
- Conservative first attempts
- Incremental adjustments
- Risk assessment
- Using data to inform decisions
Troubleshooting
- Quick fixes for common problems
- On-the-spot calculations
- Backup plans
- Adapting to unexpected results
