Lesson 3: Operations with Angles & Spur Gears
Duration of Days: 2
Lesson Objective
SWBAT: Perform addition and subtraction of angular measurements (Degrees/Minutes).
Identify the parts of a spur gear and calculate Pitch Diameter and Addendum using formulas.
How can we use scaling (ratio and proportion) to make a machine move faster or slower?
What happens to a gear train if the "Pitch Circle" is calculated incorrectly?
Ratio, proportion, spur gear, pitch circle, pitch diameter, addendum, dedendum, clearance, torque, gear train.
CTE.MFG.C.11 (Identify and use common power transmission components)
CCSS.Math.7.RP.A.2 (Recognize and represent proportional relationships).
Students perform calculations with angles and apply them to gear logic. The purpose is to understand how gears use geometry to transfer torque and speed.
DOK Level: 3 (Strategic Thinking)
Support: Provide physical plastic gears that students can mesh together to see the relationship between size and rotation.
Extension: Calculate the "Gear Ratio" for a three-gear train and determine the final output RPM.
"The Gear Spec Sheet" – Given a gear's diametral pitch and number of teeth, students must calculate all critical dimensions for production.