The European Olympiad of Experimental Science (EOES) is an annually held team-based science competition for the European Union's (EU) school students to display their capabilities in natural sciences. Since 2021, the EOES has replaced the identically structured European Union Science Olympiad (EUSO), which was founded in 2003, following a rift with its Founder and President Dr. Michael A. Cotter PhD of Dublin, Ireland, in the wake of the cancellation of EUSO 2020 due to the COVID-19 pandemic. The competition is open to second-level-school, or secondary school, science students who are 15 years of age or younger prior to the competition. Each participating country sends two three-student teams who compete in two intellectually challenging and collaborative tasks. The tasks are designed to connect the branches of science, provide relevant and inquiry-based challenges, engage all team members, support self-pacing, prompt higher-order and creative thinking, and encourage substantive communication.Tasks of the European Union Science Olympiads 2003–2007. Challenging Interdisciplinary Science Experiments. Volume 1 Editors: Dr. Michael A. Cotter & Dr. Stefan Peterson Publisher: Waxmann Verlag GmbH, Münster, Germany (2013) [autor]=PER106003&tx_p2waxmann_pi1[buch]=BUC123216

History In 1994-1997 Dr. Michael A Cotter along with a number of Dublin City University (DCU) academics, with funding provided by the Department of Education and in partnership with DCU, Queens University Belfast (QUB) and Ulster University (UU) established the Irish Science Olympiads (ISO) as the first stage in selecting Irish second level students to represent Ireland at and compete in the International Science Olympiads (IBO, IChO, IPhO & IOI) as All-Ireland student teams.

The European Union Science Olympiad was founded by Dr. Cotter in 2003. Research Gate website, The First EU Science Olympiad (EUSO): a model for science education article by R O’Kennedy, M Burke, P van Kampen, P James, M Cotter, W R Browne, C O’Gagain and E McGlynn (Dublin City University), published in the Journal of Biological Education (2005), page 58 Dr Cotter had founded the Irish Science Olympiad (ISO) in 1994 and he aimed to create an international, more practical-based general science competition for young EU students. European Union Science Olympiad website, EUSO 2003-2019 The competition was held from 2003 to 2019, with the 2020 edition being cancelled due to the COVID-19 pandemic. This led to a rift between Dr Cotter and other organisers, which resulted in the EUSO being replaced by a new competition with near-identical aims, the European Olympiad of Experimental Science (EOES), from 2021 onwards.

EUSO 2003 The first EUSO was held in Dublin, Ireland, on 6–13 April 2003. The Director was Dr. Michael A. Cotter. Seven countries attended: Belgium, Germany, Ireland, the Netherlands, the United Kingdom, Spain, and Sweden. Switzerland sent an observer. The opening and closing ceremonies took place in the Mansion House attended by Minister of State at the Department of Agriculture and Food Noel Treacy TD; Minister of State at the Department of Defence Mary Hanafin TD; the Dublin Lord Mayor, Councillor Dermot Lacey; the deputy Lord Mayor; Senator Liam Fitzgerald; and Professor Malcolm Smyth, Dean of the Faculty of Science & Health at Dublin City University (DCU).

The EUSO 2003 Management Committee included:

Chairperson: Dr. Carl Ó Dálaigh

Director: Dr. Michael A. Cotter

Administrator: Ms. Sonya Mc Kenna

Scientific Committee: Prof. Richard O'Kennedy, Dr. Paraic James, Dr. Paul van Kampen, Dr. George Porter

Senior Examiners: Dr. Ciarán Fagan, Dr. Wesley Browne, Dr. Enda McGlynn

The two experiments were held in the Science laboratories at DCU under the supervision of Mr. Maurice Burke, MSc.

Medals were awarded to the following teams:

Trophy & Gold medals United Kingdom (Team C)

Gold Medal Netherlands (Team B)

Silver Medals Ireland (Team C), Germany (Team C), Ireland (Team B), Netherlands (Team A), United Kingdom (Team A)

Bronze Medals Belgium (Team A), Germany (Team A), Germany (Team B), Ireland (Team A), Spain (Team A), Sweden (Team A), United Kingdom (Team B)

At the GB meeting, attended by all seven country coordinators, the 2003 edition of the Constitution was agreed upon. The main changes included the reduction of the student participants’ age to "sixteen on the previous December 31st" and the amalgamation of the role of country coordinator with one of the country mentors.

EUSO 2004 Fifteen EU countries participated in the second EUSO in Groningen, the Netherlands, on 2–8 May 2004. The Director was Drs. Hans Jordens. The host country invited the seven countries that participated in the first EUSO in Dublin in April 2003. They were represented by a total of 19 teams (57 Students): Belgium (2 teams), Germany (3 teams), Ireland (3 teams), Netherlands (3 teams), Spain (3 teams), Sweden (3 teams) and the United Kingdom (2 teams). Each country also sent mentors for Biology, Chemistry, and Physics.

Medals were awarded as follows: Gold medal and EUSO Trophy: Germany (Team B).Gold medal: Germany (Team C).Silver Medals: Sweden (Team C), Netherlands (Team C), Germany (Team A), Ireland (Team A), Belgium (Team A), United Kingdom (Team A) and Ireland (Team C).Bronze Medals (in alphabetical order): Belgium (Team B), Ireland (Team B), Netherlands (Team A), Netherlands (Team B), Spain (Team A), Spain (Team B), Spain (Team C), Sweden (Team A), Sweden (Team B) and the United Kingdom (Team B).

Scientific Observers represented eight countries that joined the EU in 2004. These countries were Cyprus, Czech Republic, Estonia, Greece, Latvia, Malta, Poland and Slovakia. These countries, and the seven countries listed above, were invited to send a full delegation to the EUSO 2005.

EUSO 2005 The third EUSO was held in Galway, Ireland, on 14–21 May 2005. The Directors were Dr. Michael A. Cotter & Mr. Bernard Kirk. The experiments were developed by and held in NUI Galway and GMIT under the supervision of Dr. Paraic James (DCU). The Patron was Mr. Noel Treacy TD, Minister for European Affairs.

A constitutional change (3.2.1) in 2004 reduced the delegations to two teams with three science students in each and a Mentor for each discipline (Biology, Chemistry, and Physics), with one acting as the Country Coordinator and one acting as the Head of the Delegation.

Ten countries were represented by a total of 18 teams (54 Students): Belgium (2 teams), Cyprus (2 teams), Estonia (2 teams), Germany (2 teams), Ireland (2 teams), Latvia (1 team), Netherlands (2 teams), Slovakia (1 team), Spain (2 teams) and Sweden (2 teams). Each country also sent three mentors. The United Kingdom sent a Scientific Observer.

Medals were awarded as follows: Gold Medal & EUSO Trophy: Slovakia (Team A).Gold Medal: Germany (Team B).Silver Medals: Estonia (Team A), Germany (Team A), Belgium, (Team A), Spain (Team A), Ireland (Team B), Netherlands (Team B), and Netherlands (Team A).Bronze Medals (in alphabetical order): Belgium (Team B), Cyprus (Team A), Cyprus (Team B), Estonia (Team B), Ireland (Team A), Latvia (Team A), Spain (Team B), Sweden (Team A) and Sweden (Team B).

EUSO 2006 The fourth EUSO was held in Brussels, Belgium, on 2–8 April 2006. The Director was Mr. Victor Rasquin. The experiments were developed by and held in Vrije Universiteit van Brussel (VUB) and the Université Libre de Bruxelles (ULB). The Coordinators were Prof. Dr. Luc Leyns and Roosje Van Den Driessche and the chairman was Prof. Dr. Louis De Vos. The Patron was Her Majesty, Queen Paola of Belgium.

A delegation of two teams (three students in each) and a mentor for each discipline (Biology, Chemistry, and Physics) represented participating countries. One mentor was the Country Coordinator and Head of the Delegation.

Twelve countries were represented by a total of 23 teams (69 Students): Belgium (2 teams), Cyprus (2 teams), Estonia (2 teams), Germany (2 teams), Greece (2 teams), Ireland (2 teams), Latvia (1 team), Netherlands (2 teams), Slovakia (1 team), Spain (2 teams), Sweden (2 teams) and the United Kingdom (2 teams). Each country also sent three mentors. Denmark sent a Scientific Observer.

Medals were awarded as follows: EUSO Trophy & Gold Medal: Germany (Team A).Gold Medal: Latvia (Team A) and Netherlands (Team B).Silver Medals: Germany (Team B), Slovakia (Team A), Ireland (Team B), Estonia (Team A), Netherlands (Team A), Estonia (Team B), Belgium, (Team B), Slovakia (Team B), Spain (Team A) and Ireland (Team A).Bronze Medals (in alphabetical order): Belgium (Team A), Cyprus (Team A), Cyprus (Team B), Greece (Team A.), Greece (Team B), Spain (Team B), Sweden (Team A), Sweden (Team B), United Kingdom (Team A) and the United Kingdom (Team B).

EUSO 2007 The fifth EUSO was held in Potsdam, Brandenburg, Germany on 25 March – 1 April 2007. The Director was Dr. Eckhard Lucius; Vice Directors, Dr. Marlen Fritzsche and Matthias Griessner; Secretary, Renate Glawe. The experiments were developed by and held at the University of Potsdam. The chairman was Professor Thomas Altmann.

Sixteen EU countries were represented by a total of 29 teams (87 Students). Delegations included one or two teams of three students, and a mentor for each discipline (Biology, Chemistry, and Physics). One mentor was the Country Coordinator and Head of the Delegation. Austria and Bulgaria sent Scientific Observers. International guests from Indonesia and Taiwan represented the IJSO.

Teams: Belgium (2 teams), Cyprus (2 teams), Czech Republic (2 teams), Estonia (2 teams), Germany (2 teams), Greece (2 teams), Ireland (2 teams), Latvia (1 team), Lithuania (1 team), Luxembourg (2 teams), Netherlands (2 teams), Slovakia (2 teams), Slovenia (1 team), Spain (2 teams), Sweden (2 teams) and the United Kingdom (2 teams).

Medals were awarded as follows: EUSO Trophy & Gold Medal: Germany (Team B). Gold Medals: Germany (Team A), Spain (Team A), Estonia (Team A) and Netherlands (Team A).Silver Medals: Slovakia (Team A), Lithuania (Team A), Latvia (Team A), Ireland (Team B), Slovakia (Team B), Estonia (Team B), Ireland (Team A), United Kingdom (Team A), Spain (Team B) and Netherlands (Team B).Bronze Medals (in alphabetical order): (Teams A); Belgium, Cyprus, Czech Republic, Greece, Luxembourg, Slovenia, Sweden, (Teams B); Belgium, Cyprus, Czech Republic, Greece, Luxembourg, Sweden and the United Kingdom.

EUSO 2008 The sixth EUSO was held in Nicosia, Cyprus, on 11–17 May 2008. The Director was Mikis Hadjineophytou. The Organizing Committee was assisted by the Director of the Ministry of Education and Culture, Olympia Stylianou. The experiments, carried out by the students at the University of Cyprus, were developed by the Scientific Committee composed of Dr. Epaminondas Leontides, Chemistry Professor at the University of Cyprus, Dr. Christina Sidera, Dr. Constantinos Phanis, Mr. Anaxagoras Hadjiiosif and Mr. Andreas Papastylianou.

Twenty-one EU countries were represented by a total of 33 teams (99 Students). Delegations included one or two teams of three students, and a mentor for each discipline (Biology, Chemistry, and Physics). One mentor was the Country Coordinator and Head of the Delegation. Hungary, Portugal, and the United Kingdom sent Scientific Observers.

Teams: Austria (2 teams), Belgium (2 teams), Bulgaria (2 teams), Cyprus (2 teams), Czech Republic (2 teams), Denmark (2 teams), Estonia (2 teams), Germany (2 teams), Greece (2 teams), Ireland (2 teams), Latvia (1 team), Lithuania (2 teams), Luxembourg (2 teams), Netherlands (2 teams), Slovakia (2 teams), Slovenia (1 team), Spain (2 teams) and Sweden (2 teams).