## Introduction: Copper Railways

Copper Railways takes on the thought process of an engineer as s/he finds the best route for a train to go. It uses copper to act as the high-speed railways and resistors to simulate slower railways. It is then connected to an LED (or two) to visualize the speed of the trains on those railways. Teams will compare differing routes. This lesson gives the students experience with an engineering problem and an analogy with basic circuitry.

Supplies

Tools

• Computer
• Printer

## Step 2: Construction

1. Start by printing out a preferred map. Mine came from USHSR.
2. Tape down the LEDs to the destination and checkpoints, pointing them in such a way that positives on the LEDs connect to positives of the batteries and negatives to negative.
3. Tape down resistors (I used 5k1) on the slower tracks. My map had them in gray.
4. Put tape around the back to complete the circuit. I also folded the tape, at the battery, so that the batteries could be replaced.
5. Have your students choose the route that they believe is fastest
6. Stack two batteries on top of each other and complete the circuit
7. Show what happens when they go through the resistor
8. Dimmer LEDs = Slower routes
9. Compare different teams