lightWheels Teacher’s Guide


lightWheels

Teaches physics concepts of force, speed, and mass. For Ages 8-12.

Duration: 1 hour

GRADE LEVEL
Elementary (ages 8-10)
Middle School (ages 11-13)

DIFFICULTY
Intermediate

SUBJECT
Engineering
Science

MODULES & ACCESSORIES USED (6)
dc motor (2)
power (1)
fork (1)
motorMate (1)
battery + cable (1)

OTHER MATERIALS USED (4)
Balsa wood (we used 3/16″ thick) 1
Balsa wood stick for rear shaft (we used 1/8″ thick) 1
LEGO wheels 1
Sugru (silicone modeling clay) 1

TOOLS USED
Laser cutter

ADDITIONAL FILES
https://lb-community.s3.amazonaws.com/uploads/user/1750/d3d404f9-43cf-49bd-8d94-a2b4bb574203.AI
https://lb-community.s3.amazonaws.com/uploads/user/1750/b1fdfa2f-1bab-46da-bc43-d5c24b704de9.AI

LESSON GUIDE

STEP 1 : Weigh in

Take your littleBits car and weigh it on the scale. Note the weight in kilo-grams.

STEP 2 : Length

Note the length of the ramp in meters

STEP 3 : Roll it!

Place the ramp flat on the floor. Time how long it takes the car to go across the ramp.

STEP 4 : Create an incline

Position the ramp so that it is at an incline of approximately 5° (you can either have someone in your group hold it there, or you can prop the ramp up somehow). Run the car across the ramp again, timing how long it takes. Do you notice any difference?

STEP 5 : Increase the incline

Increase the incline of the ramp by another 5° and run the car up the ramp, again noting time and any difference you experience

STEP 6 : Continue climbing…

Continue this process until the car is no longer able to move up the ramp, or the ramp is at such a steep incline that the car does not stay on the ramp without falling backwards off the ramp

STEP 7 : Stalled?

At what angle was the car no longer able to move up the ramp?

STEP 8 : Let’s analyze

Using the data you’ve collected and all your physics knowledge to date, is there any way to calculate the force or power of the motors on the car? If so, try to give an estimate of what you believe the force to be. If there is no way to calculate the force/power of the motors, then explain what information you would need that you don’t have in order to come up with the answer.

STEP 9 : Use littleBits

Since the amount of electricity that powers the motors is con-trolled by the amount of light a sensor in the middle of the car receives, is there a way you could use the littleBits starter kit to make your car move slowly, medium quick, or as fast as it can? (Consider how an LED and a potentiometer near the light sensor in your car might act as a controller.)

STEP 10 : Repeat the experiment

If you can get a speed controller working with the littleBits star ter kit, then weigh your car again (including the controller) and run the experiment again

STEP 11 : Reflect

Throughout this experiment, did everything happen the way you expected it to? If so, lucky you! If not, what factors do you think contributed to the discrepancies in your outcomes? Physics often relates to ideal situations and perfect scenarios – what about this experiment would account for derivations from your anticipated outcome?