AâB 1 AâC 1 BâA 1 BâC 1 CâA 1 CâB 1
GearHeads Today you will be learning about one of the six types of simple machines: the wheel and axle. The wheel we will be using is a toothed wheel called a gear and is one of the most common variations on the standard wheel and axle machine. You will be learning about the relationship between gear diameters, tooth count, and rotations as well as how to calculate mechanical advantage.
Write out the six steps of the scientific method.
Write out the three problem statements.
Research the following terms: mechanical advantage, gear, wheel & axle, diameter, gear mesh, radians, gear ratio, gear system, rotational inertia, torque, gear train.
Write three hypotheses.
Using short bolts and the gears labeled “A,” “B,” and “C” complete the following experiments while recording your data.
Number of teeth: A __________, B___________, C__________
Diameter: A __________, B___________, C__________
input turns output
A B A C B A B C C A C B
Gear#1
Gear #2
Mechanical Advantage
# Rotations
# Rotations
MA using # Teeth
MA using diameter
MA using # rotations
Output/Input
Output/Input
Input/Output
1 1 1 1 1 1
Put a 150g weight on the input bar. Add weight to the output bar until the gears are balanced.
Input torque
Output torque
Gear Ratio
Transmitted torque
(from previous section)
Input/output
150g 150g 150g 150g 150g 150g
A B A C B A B C C A C B Questions
1) For gears, mechanical advantage is also called __________________________.
2) Which was the easiest way to calculate mechanical advantage for gears?
3) What was the relationship between mechanical advantage (gear ratio) and transmitted torque?
4) What did you notice about the rotation direction of the gears? Set up all three gears. What do you notice about the rotations direction now?
5) If two gears were the same size what would be the mechanical advantage? What might be one reason to use them?
6) How does the force needed when A turns C compare to when C turns A?
Write your three conclusions
Write out the six steps of the scientific method.
Write out the three problem statements.
Research the following terms: mechanical advantage, gear, wheel & axle, diameter, gear mesh, radians, gear ratio, gear system, rotational inertia, torque, gear train.
Write three hypotheses.
Using short bolts and the gears labeled “A,” “B,” and “C” complete the following experiments while recording your data.
Number of teeth: A __________, B___________, C__________
Diameter: A __________, B___________, C__________
input turns output
A B A C B A B C C A C B
Gear#1
Gear #2
Mechanical Advantage
# Rotations
# Rotations
MA using # Teeth
MA using diameter
MA using # rotations
Output/Input
Output/Input
Input/Output
1 1 1 1 1 1
Put a 150g weight on the input bar. Add weight to the output bar until the gears are balanced.
Input torque
Output torque
Gear Ratio
Transmitted torque
(from previous section)
Input/output
150g 150g 150g 150g 150g 150g
A B A C B A B C C A C B Questions
1) For gears, mechanical advantage is also called __________________________.
2) Which was the easiest way to calculate mechanical advantage for gears?
3) What was the relationship between mechanical advantage (gear ratio) and transmitted torque?
4) What did you notice about the rotation direction of the gears? Set up all three gears. What do you notice about the rotations direction now?
5) If two gears were the same size what would be the mechanical advantage? What might be one reason to use them?
6) How does the force needed when A turns C compare to when C turns A?
Write your three conclusions
