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Ninth Experimental Physics Olympiad (EPO9)

Sofia Branch (SB) of the Union of Physicists in Bulgaria (UPB), together with the Society of Physicists of Macedonia (SPM) and Regional Society of Physicists from Strumica (RSPS) are organizing the 9th Experimental Physics Olympiad (EPO9).

The Olympiad will be held in a hybrid mode: online and on-site participation, and the ranking will be separate for the two different modes. The Olympiad will be held on May 7 (Saturday), 2022. The ranking of the best participants will be announced on the next day. The date of the EPO9 was postponed to better times in this school year.

Online participants will receive the experimental set-ups by conventional mail prior to the Olympiad. The task of the Olympiad will be available online and sent by e-mail at the day of the Olympiad at 11:00 Central European Time (CET) (12:00 Sofia time). Students must have 2 multimeters, one of which should have temperature measurement capability with the corresponding thermocouple, connecting cables for the multimeters, a calculator, squared paper (graph paper), writing paper, and a pen. Online participants must take photos or scan their work and send it to the email by 16:00 CET, i.e. 4 hours from the beginning of the Olympiad.

Information for the on-spot Olympiad held simultaneously in Skopje, R. N. Macedonia will be announced later.

Registration. There is no registration fee. The Olympiad will consist of two rounds: 1) Selection round, where participants are asked to send the solution of a qualification task to by 1st of April 2022 (hard deadline). The task is available online from the site of EPO. Simultaneously with the solution of the task the participants has to send to a) His name as they wish to be written in the certificate for the participation, b) The name of the School, c) Town and Country d) Name of the mentor (if any) e) personal e-mail which the participant will use during the Olympiad using Zoom platform; the registration must be sent from this address.

2) The Olympiad round will be held on 1st of May 2022. The task will be sent to the participants by email or a printed copy will be given in the auditorium for the on-spot Olympiad.


On-line participants: after submission of the task for the first round to participants have to submit to the same address the detailed street address to whom the set-ups has to be sent by organizers using regular post or another courier company: Name, Mobile phone number, Street address, Town, ZIP code, Country. Post expenses are covered by the receiver. For several participant from one school is better to use the institution address.

On-spot participants will receive the set-ups at the place of the Olympiad in Skopje, which will be described in detail later.

Task for the selection round. One of the purposes of this task is to establish contact between the participant and the organizers of EPO9, we practically repeat the task from former Olympiads. The solution of the problem has to be sent to the organizers, preferably in PDF (scanned or photographed). The student must have 2 multimeters. To start, measure the voltages of their batteries; it is good to have them replaced this year. For each of the multimeters, prepare a separate table for their internal resistances RV when switched to all of their settings when functioning as a voltmeter. Similarly, for all possible settings when the multimeters are switched to an ammeter, measure their internal resistances RA. Calculate the ratio ZV/A=RV,min/RA,max between the smallest RV value and the largest RA value. Also measure the voltages UΩ which the multimeter generates for all ranges when it is switched on as an ohmmeter. Next, take a potentiometer, a battery, a resistor, and cables with crocodile clips, and measure the voltage U and current I through the resistor, while applying different voltages to the resistor. Present the results first in a table (n, Un, In), n=1,2, … , N; and  then graphically. For each of those N measurements, plot the experimental point on squared paper, with the current horizontally (abscissa) and the voltage vertically (ordinate). Draw a line of best fit. At the ends of this line, select two points A and B and measure the differences of their voltage ∆U=UBUA and their current ∆I=IBIA, and calculate the ratio R= ∆U/∆I. What is the dimension of this slope of the line? What law did you measure, and what accuracy did you achieve? Older students can compare the graphical solution with the results of the linear regression calculated from the experimental data. This is a good estimate of the error in processing experimental data. If you can find some light emitting diodes (LED), measure the relationship between current and voltage I(U). The current from the batteries must always pass through a protective resistance of at least 20 Ω, because the diodes can be burnt easily. Draw carefully the dependence of current as a function of voltage I(U) when current is less than 10 μA.

Additional task: Measure the time dependence the temperature T(t) of a hot cup of tea or hot water until it reaches approximately room or even better outside winter temperature. Choose the optimal measurement interval (time between successive measurements), meaning do not take excessive and almost equal temperature measurements or too few measurements that will not reveal the cooling behavior in time. Plot this dependence on a graph: time t in the abscissa temperature in Celsius degrees in the ordinate T.

Age categories. Participants in the Olympiad are separated in the following categories: S, M, L, and XL. For different countries the educational system is different, but if physics is to be studied for 6 years on average at school, the S category is for the first 2 years, the M category is for the middle 2 years, and category L is for the last 2 years of high school. The XL category is for university students. A separate ranking will be made for each age group. The task of the Olympiad is actually a sequence of many related tasks, given as different sub-tasks with increasing difficulty – every participant has to do the best to solve these sub-tasks. The Olympiad is in experimental physics, but with these measurements taken, the understanding of what is being done will be necessary. Thus, there will be several entirely theoretical sub-tasks. The authors of the tasks have combined experiments described in various textbooks.

Around and after the Olympiads. The Sofia branch of SFB, the Regional Society of Physicists from Strumica (RSPS) and Society of Physicist of Macedonia (SPM) have been organizing such Olympiads since 2011 and they are gradually becoming a traditional part of out-of-school physics education; here we have to mention participation from many countries between Kazakhstan and Canada, Greece and Russia. The Experimental Physics Olympiad (EPO) has gradually become a forum for colleagues teaching physics, complementing the social life of the collegium. An analysis of the 8 Olympiads showed that students learn a lot during the Olympiads themselves, and when they return to class they can illustrate the solution to their classmates. Thus, the Olympiad complements the informal out-of-school work indispensable in the crating of future professionals. After the Olympiad, participants are encouraged to repeat the experiment looking at the published solution and the work of the champion, arriving to an even better solution. That is why the set-up hast to be considered as a gift from the organizers. If they wish, at the end of the school year, the participants may donate the set-up to the physics laboratory of their school. In such a way, the Olympiad directly affects the level of teaching in each school that has EPO participants. Next year, the edited EPO task will be published in a methodological journal and will become a basis for further work by colleagues developing experimental work in physics education.

Updated information can be found on the website of the SB of UPB .

Please spread this message among students and teachers.

With best regards,

EPO, 24 November, 2021