DRIVETRAINS

This activity is intended to get your Explorers engaged and to serve as a lead-in to the main event.

This activity demonstrates how gears affect the power required to propel a vehicle.

In a safe area such as a parking lot, take the heart rate (and blood pressure if you have the ability and means) of three of the Explorers. Record these numbers.

Have one of these Explorers get on the bike and ride as fast as possible for one minute, using the bike’s lowest gear. When the time is up, measure and record the Explorer’s heart rate and/or blood pressure. Repeat this activity with a second Explorer using a neutral or middle gear and with a third Explorer using the bike’s highest gear. (Note: As time allows, this can be done with each member of the post.)

Compare the initial and final heart rate and/or blood pressure readings.

Begin the main event by asking the following questions:

• How difficult was it to get the bike moving in your assigned gear?
• Did it get easier or more difficult as you went faster?
• What did you notice about the difference in the amount of effort it took, based upon the differences in your respective heart rates or blood pressures?

Try to guide the discussion toward the conclusion that choosing the proper gear for the conditions will increase performance with the least amount of expended energy. Relate this to the purpose of gears in a drivetrain.

It is important that your Explorers have the opportunity to get their hands dirty and actually experience the workings of an engine. Find ways in which each participant can touch and manipulate the various parts of the drivetrain. If possible, have both manual and automatic transmissions available. You may also choose to break this activity into two meetings and focus on each type of transmission separately.

Raise your demonstration vehicle so that everybody can see the various components of the drivetrain, and give an overview of how each part contributes to the movement of the vehicle.

Depending upon the amount of time available, you may wish to have the Explorers drop the transmission out of the demonstration vehicle, or simply have a transmission available for them to work on.

Guide the Explorers through the process of dismantling and rebuilding the transmission. During this process, talk about the following:

• Gears and gear ratios
• Torque versus speed
• Pressure plates and hydraulics
• Transmission fluids and lubricants
• Transaxles and differentials
• FWD, RWD, and 4WD/AWD configurations

As each part is inspected, discuss its function within the drivetrain. Explain the principles associated with gears and power loss or gain through their use or the way in which they are configured.

When you are done, give each participant an opportunity to identify each of the parts you have worked on and explain their function. Allow time for questions.