Humanities Preparatory Academy

Consortium school

Physics is the study of forces and motion. In this course we will use equations to describe the motion of objects, from the sudden stop of an express A-train to the arc of a home run. We will begin by describing (mathematically and graphically) the motion of objects moving in only one dimension, and then discuss the fundamental concepts of force, energy, and torque.

Students will perform several investigations using mouse trap powered race cars. The students will then design their own experiment based on testing a modification of their race car. This experiment will culminate in a Science or Math PBAT.

Conceptual Physics - Paul Hewitt

PBAT Design & Research Guide
For your PBAT experiment, you will make a series of modifications to your race car and measure the effect these modifications have on your race car’s performance. This guide will help you design your experiment and begin to write the first key sections of your PBAT.

In your experiment, you can either measure the effect of one modification, or compare the effect of two different modifications. The following are some examples of possible modifications:
Increase / decrease mass
Change length of lever arm
Increase / decrease wheel size
Increase traction on wheels
Move location of mousetrap
Change wheel design
Change wheel mass
Change wheel to axle ratio

You can choose from any the modifications listed above, or another modification you propose. Your modification must be incremental (you can gradually increase the modification) and reversible (you can undo the modification). For example, if you modify the length of the lever arm, you must perform tests using a series of different lengths, and you must be able to go back to your original length. All modifications must be approved by Paul.

Research & Hypothesis:
The research section of your paper will serve two functions. First, you will describe how your unmodified racecar (your Control) works, including any relevant physics. You will then describe the physics concepts behind your modification(s). The concepts will depend on your chosen modification(s), but will likely include: Newton’s Laws, rotational motion, torque, friction, etc. Once you have chosen your modifications, you should read the relevant chapters in the textbook. Your research section should be ~2 pages in length.
After you have presented your research, you will present your hypothesis. Your hypothesis will be a specific prediction about the outcome of your experiment that is grounded in your research. Your prediction must be specific as possible so that you can determine the accuracy of your data. Your research should give you some idea of how great the effect of your modification will be --you may not simply say that your car will go faster or farther, your prediction must be quantitative. Example: Because of the relationship between wheel diameter and velocity, we predict that, by doubling the radius of the drive wheels, the final velocity of the car will double.

Your procedure should be a detailed description of how you will perform the experiment. You must identify the controls and variables and describe the significance of each. You must also include a complete step-by-step set of instructions for performing your experiment, describing how you collect data for each trial. What quantities will you measure? How many data points will you take? How many trials will you run? You must also identify potential sources of error and describe how your procedure will minimize the effect of these errors.
Rule of thumb: Someone outside of your group should be able to repeat your experiment using your procedure and get similar results. This means that your procedure should contain all the relevant instructions and details needed to successfully perform your experiment.
Your procedure should be ~2 pages in length.

Data Collection:
For this proposal you should include the data table you plan on using for your experiment. Although you will not need to include a blank data table in your final PBAT, this will help you as you write your procedure.

Media Used:
Significant Assignments: 

Students must submit a proposal for the experiment they wish to perform using their race-car.

Sample PBATs: 
How does the length of the mousetrap lever-arm affect the acceleration of the race car?
How does the traction of the wheels affect the speed of the race car?
How does the size of the axle affect the speed of the race car?
What is the relationship between the mass of the drive wheels and the final speed of the race car?