EDCI 592C

Chin-Hsueh Lee

Car Control Lesson Plan

Main Concept:

When two different sized gears are connected, there is a difference, the work that the

gears do changes depending on which gear is the driver. This activity explores how a small

gear wheel connected to a larger gear wheel affects the way they work.

Math and Science Concepts:

1. Gearing up and gearing down, directions

2. Formula to determine gear ratios

3. Ratio concept

4. The energy generated with different size of gears

Grade Level:

6th-9th Grade

Objectives:

1. Understand the relationship between gears of different sizes can be expressed using

mathematics

2. When gears of different sizes are put together, they behave differently depending on

which gear is turned. This behavior determines which type of gear is used in machines

3. Compare the type of energy we have to put into these machines to make them work

4. Understand the size of gear does affect the energy output

5. Familiar with ratio concept

6. Using mathematics formula to calculate ratio

7. Understand gearing mechanism

Materials

* 8-stud beam X1

* 8-stud length axles X2

* Bushings X2

* 8-tooth gear wheel X1

* 24-tooth gear wheel X1

Procedures:

1. Connect the 8- and 24- gear wheels together on the two 8-stud beam by the two axles

using the two bushings to fix the position.

2. Make sure the two gear wheels are in contact with each other.

3. Turn the axle of the large wheel gear and have the students write observation.

4. Turn the axle of the small wheel gear and have the students write observation.

5. Turning the small gear first makes the larger one move slower. This means the driver

gear is smaller than the follower.

6. Turn the small wheel and notice how easy to turn- Determine gear ratios, use the formula

as presented below by using the formula: Gear Ratio = # of teeth on the driver divided

by # of teeth on the follower. In this case, the gear ratio between the small one and the

arge one is 8/24 which is 1:3. This means the small wheel must turn three times to turn

large wheel once. It also indicates that the small wheel will generate three times more

energy ( output ) than the large one. The output is called torque. This enables a rider to

go up a hill easier..

7. Step 6 can be done in an opposite way by turning the large wheel. The whole result will

be complete opposite.

8. Have the students write journal about what they learned or make a presentation.