The Mission: The Emerald Energy Project
Attention, Engineers!
Lucky the leprechaun has dropped his pot of gold into a deep canyon beneath a rainbow. The canyon is 11 inches deep, and once the sun sets, the gold will vanish forever!
The good news? A strong Irish Wind is blowing through the valley.
Engineering Goal: Your mission is to design and build a wind-powered turbine that converts wind energy into enough rotational motion and torque to lift the pot of gold (1 penny) to the top of the tower.
The Emerald Isles are counting on you to get that pot of gold back to the end of the rainbow!
Engineering Concepts: Powering the Pot of Gold
Before you build your turbine, make sure you understand the three key forces that will determine whether the gold rises or stays lost in the canyon!
1. Blade Pitch (Angle): Blade pitch is the angle of the blade compared to the wind. It determines how much wind force your blades will capture. Changing pitch changes how the wind pushes on the blades. Some angles favor faster spinning, while others favor stronger twisting force (torque). The best angle depends on your load and friction.
Think of it like holding your hand out of a car window. If your hand is flat, the air slips by. But if your hand is tilted, the air pushes harder against your hand. Pitch is measured in degrees using a protractor. In this challenge, pitch directly affects how much torque your turbine produces.
2. Torque (Twisting Force): Torque is a twisting force that causes something to rotate. Lifting requires both enough torque and enough rotations to wind the string. A design can have torque but be too slow, or spin fast but stall under load.
- If your blades spin very fast at first, but stop once the string tightens, and the cup does not lift, you likely have high speed, but low torque.
- If your turbine lifts the gold, but the blades spin slowly, you likely have higher torque.
Your goal as Emerald Engineers is to generate enough torque to lift the pot of gold (1 penny) 11 inches.
3. Friction: Friction is a force that resists motion when surfaces rub together. In your system, friction may occur:
- Between the axle and tower.
- Where the string wraps around the axle.
- Between the cup and the tower.
Friction reduces efficiency because it steals energy that could be used to lift the “gold.” Engineers try to align moving parts carefully, keep surfaces smooth, and reduce rubbing wherever possible.
Engineering Log
Team Name:
Team Members:
Step 1: Ask
| Define the Problem: What is the engineering goal? (Hint: Page 1) |
Design Constraints
- Fan speed must remain constant.
- The turbine must be at least 11 inches tall.
- Distance from the fan must remain constant.
- The load must be exactly 1 penny in a medicine cup.
- Only provided materials may be used.
- No touching the turbine during testing.
Step 2: Imagine
Design Decisions
What design features can we control?
- Number of blades
- Blade angle (pitch)
- Blade size
- Blade shape
- Axle type
- Structure stability
| Which design features do you predict will most affect torque? Which design features do you predict will most affect speed? |
Step 3: Plan
In your Initial Design Sketch, include:
- Number of blades
- Blade angle, for example
- 15 degrees (low pitch)
- 30 degrees (medium pitch)
- 45 degrees (high pitch)
- Blade shape
- Axle placement
- Where the string wraps
- How the string connects to the axle and the cup
| Sketch Box Predicted strengths of this design: Predicted weaknesses of this design: |
Step 4 (Create)
Build Your Prototype
Put your plan into action! Use the materials provided by your teacher to build your prototype.
How to Measure Pitch Before Attaching Blades to the Axle
- Lay your blade flat on the desk.
- Draw a straight line at the bottom of the blade (this will attach to the axle).
- Place the center of your protractor at the corner of the blade base.
- Mark your chosen angle.
- Lightly fold along that angle to create a small tab.
- Tape the tab securely to the axle.
Before testing, check:
- Blades are evenly spaced.
- Blade angles are measured.
- The axle spins freely.
- The string wraps smoothly.
- The tower is stable (you will need to tape it down to the desk)
Step 5: Test
Start each test with the cup on the desk with the string connecting the cup to the axle.
Data Collection
- Load: 1 penny
- Height: 11 inches
Trial Data
| Trail # | Blade Angle | # of Blades | Lift Time (sec)* | Observations |
|---|---|---|---|---|
1 | ||||
2 | ||||
3 |
Step 6: Improve
Redesign and Final Plan
| What changes did you make? Why did you make these changes? Final Design Sketch |
Step 7: Re-Test
Conduct Tests with Improved Design
Trial Data
| Trail # | Blade Angle | # of Blades | Lift Time (sec)* | Observations |
|---|---|---|---|---|
1 | ||||
2 | ||||
3 |
Reflection Questions
- Did the improved design lift the load all 11 inches every time? If not, where did it stop?
- How consistent were your trials? What might explain any differences?
- What did you notice about blade speed vs. lifting power? Did a faster spin always mean a faster lift?
- What friction problems did you observe? How did they affect results?
- If your turbine stalled, what do you think was the limiting factor: not enough torque, too much friction, or structural instability? What evidence from the trials supports your response?
- Based on the data, what is one change you would test next if you had time?