3. SPUR GEARS Essential Characteristics: What things are absolutely necessary for something to be a spur gear? Non-essential Characteristics What are some things about a spur gear? Examples Provide examples of a where a spur gear is used or found. Non-examples Provide examples what is not a spur gear.

4. EssentialNon-essential ExamplesNon-examples SPUR GEARS PULLEYS WHEELS ROLLERS DIFFERENT SIZES SHAPE OF TEETH CLOCKWISE / COUNTER WORK WITH WHEELS/AXLES ELECTRIC SCREWDRIVER OSCILLATING SPRINKLER WINDUP CLOCKS WASHING MACHINE BICYCLE WHEELS CIRCULAR TEETH (EVEN) USED FOR SPEED AT LEAST TWO NEEDED PARALLEL SHAFT

5. WHAT ARE GEARS? Gears are simple machines that are used to transfer motion from one place to another. By changing the size of the gears you can also change the force required to turn the gears. They can be used to speed up, slow down, or just transfer the motion (in the form of rotation).

6. A gear is a wheel with teeth around the outer rim. A gear train requires that two or more gears be connected with same sized teeth that are the same distance on each gear. A gear ratio is when you compare the number of teeth on the gear on which the force is being applied (the drive) with the number of teeth on the gear being turned.

7. Build a TANKBOT using grey instruction duo-tangs. Modify your TANKBOT to use the tires and gears rather than the treads. Perform each of the three trials specified in Gears Exercise. After each trial record your information on your sheet then the projector table. Compare the results of each gear ratio and the time it took to travel 1 meter. On your Group Table sheet record your prediction of the fastest gear ratio and explain your choice. REMEMBER Take turns at the timing stations. Work cooperatively in your group and as a class. Encourage – this is a CHALLENGE not a CONTEST!!!