1. Two-Gear Gear Trains Driving gear is attached to motor Driven gear is attached to wheel Gears spurs (teeth) mesh together Gears rotate in opposite directions Using different size gear allows change in speed Gear ratio calculates this change

2. Complex Gear Gear Trains Gear Ratio = B, C and D are called idler gears. Why might you want to do this?

3. Compound Gear Trains Gear Ratio = How does this change things? Why might you want to do this?

4. Construct of frame out of 15-hole beams Build a stand for your frame as shown >>> Add a wheel axle & crank axle as shown below Using the parts from only one kit, construct a gear train that provides a Gear Ratio > 200 in the remaining 9 beam holes Hint: Reduce friction wherever possible Gear Train Challenge

5. Gear Train Challenge One Possible Solution Click Once More to View Gear Ratio = 225