2021 Western Kentucky Physics Olympics: Event Descriptions

Virtual 2021

Judges determine the overall winner based on each team's score in the five different events.

Do-Ahead Event: Color Blindness

For this event, each team will create at least two, and up to three simple devices to measure the inertial mass of small objects (2 to 50 grams).

Problems involving gravity, at least those assigned for introductory physics courses, always involve the mass being accelerated being exactly the same as the mass determined by dividing its weight by the acceleration due to gravity. The assertion that inertial mass and gravitational mass are identical is called the "equivalence principle."

One way to determine the gravitational mass is through the use of a "balance" scale (such as the example illustrated below. Known masses are balanced against the unknown mass, with the gravitational field of Earth acting equally on both.

Teams are not allowed to use this method in the competition. Determining an object's inertial mass is a little more complicated than determining its gravitational mass. Inertia is the resistance of an object to a change in its velocity. Inertial mass is the mass of an object by applying a force to it and interpreting the results with equations. Each team is required to design, construct, and test two separate devices based on any two of the following three methods to determine "inertial mass." Any such methods will involve balancing some known/measurable external force(s) and comparing to some know/measurable acceleration.

  1. rotational: centripetal force due to circular motion of a rotating mass can be balanced against another force acting on the mass
  2. spring constant: allow the mass to oscillate on a spring with a spring constant that has been accurately determined
  3. acceleration due to external force: Modified Atwood's Machine is a category of experiments first conceived of in the mid-1800's, which can be summarized as measuring the change in velocity for the unknown mass due to an applied force
Rules:
  1. The purpose of this initial event is to demonstrate the basic operation of at least two, and possibly three, devices to measure the inertial mass of objects between 2 and 50 grams.
  2. Teams will earn points for up to three devices. The first two devices must fit into one of the three categories listed above (rotational, spring constant, or acceleration due to an external force). The third device is allowed to be any other way of experimentally determining inertial mass, including whichever was unused from the above list.
  3. Each device must be designed and assembled by the students. Off-the-shelf instruments will not be accepted. Parts contributing toward the overall device can be pre-manufactured, but no single pre-manufactured component can account for more than 50% of the device's function.
  4. For these devices, it is not allowed to vary the amount of known mass as any part of the solution for the determination of the unknown mass. Other variable parameters can be built into each device. However, any mass which is part of the device must be kept the same - its amount may not be altered throughout the testing process.
  5. Whenever a device with moving parts is being demonstrated as part of the event, any team member within 6-feet of the device MUST be properly wearing safety glasses.
  6. Successful demonstration of each device will be assessed by four criteria:
    1. Written description of the physical principles for the device, explicitly differentiating it from a method measuring gravitational mass (such as with a balance) and from the methods used by the team's other device(s).
    2. Written and illustrated design plans, clearly showing how the device was assembled, with the source of all functional components listed.
    3. Example of the equations and calculations required to determine the mass from the demonstrated experimental results.
    4. Virtual demonstration for the judges, showing how results are obtained for two different masses provided by the team. The process of determining the inertial mass is the only aspect being evaluated, not the accuracy of the measurements (which is the goal for the following week's event).
  7. The written description, written and illustrated design plans, and examples of equations and calculations are to be sent via e-mail attachments, as either Word or PDF documents, to olympics@physics.wku.edu. All required documentation must be received by 7 a.m. CST on Saturday 20 February 2021. Documents received by 7 p.m. on Friday evening will be acknowledged with a reply e-mail from the judges.
  8. During the live judging period on Saturday morning, each device being evaluated must be able to be clearly seen by the judges via the Zoom connection. Teams are responsible for providing adequate lighting and either a movable video camera or devices which can be moved.
  9. Overall ranking for the event will be based on the sum of the scores for each device, assigned by the judges for the four criteria, with the highest score ranked in first place.
  10. In case of tie scores, the team with the highest score on the four criteria for their best device will be ranked higher. If a second tie-breaker is required, higher ranking will to the team with the highest total score for design plans.
  11. All contestants will ensure that their entry works through the application of physics principles and generally follows the spirit of the competition.

Plan-Ahead Event: Unknown Mass

For this event, each team will use any combination of their devices designed, constructed, and tested during the previous Saturday's event to measure, as accurately as possible, the inertial masses of multiple small objects (2 to 50 grams) provided by the event organizers.

Rules:
  1. Improvements can be made to the devices designed, constructed, and tested during the previous Saturday's event and to the procedure for measuring masses with those devices. However, it is not permitted to make use of a new device or new procedure.
  2. The event organizers will arrange for a designated member of each team to receive a package with multiple sealed boxes containing the masses to be measured on the day of the competition. Do NOT break the seals on these boxes until instructed by the judges during the virtual competition, Saturday 27 February 2021.
  3. Expect that the objects in the sealed boxes will not have hangers, or any place to attach a hanger. Prepare your device so the objects can be held in a bag, net, or other cradling situation.
  4. All of the team's devices and all of the sealed boxes must be in one location. It is possible for team members to not be in the same location and the sealed boxes yet still be useful. Once testing commences, work within the team can be delegated however the team sees fit. For instance, one team member (or more) could be remote from the devices and serve a vital role as designated calculator; while another might be an overall organizer or quality control officer.
  5. When the event is ready to commence, each team must demonstrate to the satisfaction of the designated judge that each of the sealed boxes containing masses to be evaluated has not been opened since it was sent out for delivery to the teams. Only after the judge announces at the start of the event may the sealed boxes be opened.
  6. our devices must be visible to the judges when demonstrated on the Zoom call its ability to magnify three different objects provided by the judges.
  7. When the judge announces the start of the event, team members can start utilizing whichever of their devices they choose to measure whichever of the unknown masses they choose. Work can be split between devices and between team members as they see fit. Objects can have their mass measured by one, two, or all three of the team's devices. Teams re-measure the mass of an object and/or can choose to keep or discard any measurement values they obtain.
  8. At the conclusion of the event, each team provides a listing with the designation associated with each of the objects that came to the team in sealed boxes, and the value for the mass (in grams) the team measured for that object.
  9. Final ranking will be determined by the sum of the percent accuracy between the established mass of each object and the values reported by the teams. For teams with identical scores, ties will be broken according to the lowest standard deviation of the all the percent differences between each established mass and its reported mass. If a second tie-breaker is required, the team who first reports its measurements will be ranked higher.
  10. All contestants will ensure that their entry works through the application of physics principles and generally follows the spirit of the competition.

Communication/Calculation Challenge: Black Hole Probe Recovery

Your team will work as a team, dividing effort however they see fit, to solve the puzzles required to open each aspect of the challenge and in the end to submit the proper code to recover the missing probe.

Impromptu Team Activity: Forces of Nature

Your team will work as a team, dividing effort however they see fit, to solve the puzzles required to unlock each subsequent aspect of the challenge and in the end to submit the proper code to unlock the door and escape your virtual confinement.

Fermi Questions: The Order of Magnitude Quiz

In this quiz, the contestants will need to quickly make assumptions for values to use in simple calculations in order to arrive at the "correct" answer, stated as the power of ten of the number that fits the accepted value. Teams will receive 8 to 10 questions to complete within 15 minutes. The teams can divide the work in any way they see fit, but only one answer per question per team will be accepted. Answers will be judged according to how many orders of magnitude the team's answer is from the judge's solution.