1. Using the pen, paper, ruler, cardboard scissors and tape, construct a height extension for the trailer by measuring the dimensions of the trailer, then drawing and cutting a correspondingly-sized foldable rectangle pattern in the cardboard.
2. Tape the extension to the trailer and measure the trailer height from the bottom of the first wheel to the apex of the trailer extension. Record the height.
3. Use the level to confirm that the pin of the force measurer and the wind tunnel are parallel to the ground.
4. Tape a piece of paper to the top of the wind tunnel, above the door and set the force measurer’s handle on it.
5. Attach the trailer to the tractor, open the wind tunnel door and insert the model into the wind tunnel.
6. Connect the loop from the Mechano beam to the hook at the base of the tractor, and then arrange the model to face directly forward. Position the model in the center of the base board.
7. Close the door to the wind tunnel.
8. Pull the handle until the spring is in a fully contracted position but the Mechano beam lever is perpendicular with the ground. On the paper, use the pen to mark this position as datum.
9. Turn on the wind tunnel fan while firmly gripping the handle of the force measurer.
10. Pull and push on the handle of the force measurer until the Mechano lever is perpendicular with the ground. At this point, push the lever in the direction of the flow (pulling the model into the direction of the flow) and wait until the lever returns to a rest position. This takes into account the difference between dynamic and static friction as it ensures the truck is being pushed by dynamic friction.
11. If the lever comes to rest perpendicular to the floor, use the pen to mark the handle’s position. If it does not, repeat step 10 until it does.
12. Repeat steps 10 and 11 after completely resetting the model’s position by moving the handle back and forth. If, on the second time, the handle position remains the same, indicate on the paper that the trial number of the mark.
13. Turn off the fan, open the door, remove the model and remove the trailer extension. Cut one centimeter off the bottom of the trailer extension and reattach it to the trailer.
14. Measure and record the trailer’s height.
15. Repeat steps 5 to 7, then 9 to 13 until the trailer extension can no longer be shortened. At that point, repeat the test without an extension.
16. Remove the paper from the top of the wind tunnel.
17. Using the calipers, measure the distance from datum to each of the markings and record each distance.
18. Convert the displacements to force by using the equation found through the calibration of the spring..
19. On the force measurer’s lever, determine the distance from the spring to the pin and the distance from the pin to the fishing line. Use these values to calculate the force on the tractor trailer.
20. Record the force on the tractor trailer for each height.

1. Measure the height of the trailer without any modification to the model. Record this height.
2. Tape a piece of paper to the top of the wind tunnel, above the door and set the force measurer’s handle on it.
3. Using the Mechano set and tape, construct an extension to increase the space between the cab of the tractor and the front of the trailer.
4. Measure the height of the trailer from its first wheel to the top and adjust the height until it matches the original height of the trailer.
5. Measure and record the distance between the end of the tractor cab and the front of the tractor along the side. Record the cab-trailer distance.
6. Use the level to confirm that the pin of the force measurer and the wind tunnel are parallel to the ground.
7. Open the wind tunnel door and insert the model into the wind tunnel.
8. Connect the loop from the Mechano beam to the hook at the base of the tractor, and then arrange the model to face directly forward. Position the model in the center of the base board.
9. Close the door to the wind tunnel.
10. Pull the handle until the spring is in a fully contracted position but the Mechano beam lever is perpendicular with the ground. On the paper, use the pen to mark this position as datum.
11. Turn on the wind tunnel fan while firmly gripping the handle of the force measurer.
12. Pull and push on the handle of the force measurer until the Mechano lever is perpendicular with the ground. At this point, push the lever in the direction of the flow (pulling the model into the direction of the flow) and wait until the lever returns to a rest position. This takes into account the difference between dynamic and static friction as it ensures the truck is being pushed by dynamic friction.
13. If the lever comes to rest perpendicular to the floor, use the pen to mark the handle’s position. If it does not, repeat step 10 until it does.
14. Repeat steps 10 and 11 after completely resetting the model’s position by moving the handle back and forth. If, on the second time, the handle position remains the same, indicate on the paper that the trial number of the mark.
15. Turn off the fan, open the door and remove the model. Use the Mechano set and tape to modify the extension to bring the trailer closer to the cab.
16. Repeat steps 4 to 9, then 11 to 15 until the test has been conducted with zero trailer-cab spacing.
17. Repeat the steps 4 to 9, then 11 to 15 with the tractor-trailer in standard configuration.
18. Remove the paper from the top of the wind tunnel.
19. Using the calipers, measure the distance from datum to each of the markings and record each distance.
20. Convert the displacements to force by using the equation found through the calibration of the spring.
21. On the force measurer’s lever, determine the distance from the spring to the pin and the distance from the pin to the fishing line. Use these values to calculate the force on the tractor trailer.
22. Record the force on the tractor trailer for each cab-trailer distance.

1. Carefully create a connecting sleeve out of duct tape to join the cab of the tractor to the trailer.
2. Use the level to confirm that the pin of the force measurer and the wind tunnel are parallel to the ground.
3. Open the wind tunnel door and insert the model into the wind tunnel.
4. Connect the loop from the Mechano beam to the hook at the base of the tractor, and then arrange the model to face directly forward. Position the model in the center of the base board.
5. Close the door to the wind tunnel.
6. Pull the handle until the spring is in a fully contracted position but the Mechano beam lever is perpendicular with the ground. On the paper, use the pen to mark this position as datum.
7. Turn on the wind tunnel fan while firmly gripping the handle of the force measurer.
8. Pull and push on the handle of the force measurer until the Mechano lever is perpendicular with the ground. At this point, push the lever in the direction of the flow (pulling the model into the direction of the flow) and wait until the lever returns to a rest position. This takes into account the difference between dynamic and static friction as it ensures the truck is being pushed by dynamic friction.
9. If the lever comes to rest perpendicular to the floor, use the pen to mark the handle’s position. If it does not, repeat step 10 until it does.
10. Repeat steps 10 and 11 after completely resetting the model’s position by moving the handle back and forth. If, on the second time, the handle position remains the same, indicate on the paper that the trial number of the mark.
11. Turn off the fan, open the door and remove the model.
12. Remove the doors from the back of the trailer and insert a rubber balloon. Blow up the balloon until it fits snugly into the trailer and tape the balloon to the trailer.
13. Repeat steps 2 to 5, then 7 to 11 with the model in a configuration with a balloon and duct tape sleeve.
14. Remove the duct tape sleeve from the truck.
15. Repeat steps 2 to 5, then 7 to 11 with the model equipped with the balloon only.
16. Remove the balloon and reattach the trailer doors.
17. Repeat steps 2 to 5, then 7 to 11 with the model in standard configuration.
18. Remove the trailer from the tractor.
19. Repeat steps 2 to 5, then 7 to 11 with only the model tractor.
20. Remove the paper from the top of the wind tunnel.
21. Using the calipers, measure the distance from datum to each of the markings and record each distance.
22. Convert the displacements to force by using the equation found through the calibration of the spring.
23. On the force measurer’s lever, determine the distance from the spring to the pin and the distance from the pin to the fishing line. Use these values to calculate the force on the tractor trailer.
24. Record the force on the model for each configuration.

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