1. EducateNXT Gearing LEGO parts required for gearing activities: GEARS 24 teeth (or 24-tooth crown) 40 teeth 8 teeth AXLES 16 x 1 LEGO Brick Bushings

2. EducateNXT Gearing A B If Gear A turns clockwise, which way will Gear B turn? Using any two gears with the same number of teeth, make the following gear system.

3. EducateNXT ABC Gearing If Gear A turns clockwise, which way will Gear C turn?

4. EducateNXT A 40 teeth B 40 teeth Gearing How many times will you need to turn Gear A so that Gear B turns one rotation?

5. EducateNXT B 40 teeth A 8 teeth How many times do you have to turn Gear A to turn Gear B one rotation? Gearing You should get five times.

6. EducateNXT A 24 teeth B 40 teeth Gearing Before you make this gear train, predict how many times you will need to turn Gear A in order to turn Gear B one rotation. Now make it and check your answer. You should get a little more than 1.5 times.What is the exact gear ratio?

7. EducateNXT 3 times 1.67 times A 8 teeth B 24 teeth C 40 teeth GEAR RATIO Gearing Multiple simple gear ratio = 3 x 1.67 = 5 Check to see that five turns of Gear A will cause one turn of Gear C.

8. EducateNXT Compound Gearing A compound gear ratio is the total multiplied gear ratio of all gears in a gearbox. It works by having a smaller gear on the same axle as a larger gear.

9. EducateNXT Compound Gearing Construct the above compound gear train with three axles.

10. EducateNXT 3 3 Compound Gearing Total gear ratio = 3 x 3 = 9 Check to see if 9 turns of A = 1 turn of B A B

11. EducateNXT Now make your own compound gear ratio. How big a gear ratio can you come up with? Compound Gearing Heres one way to do it.

12. EducateNXT Resources Gears have been drawn using EasiDraw Gear for Microsoft Word. www.myeasidraw.com www.myeasidraw.com LEGO piece diagrams in Slide 1 from www.peeron.com www.peeron.com

13. EducateNXT