Aharon Katzir

Aharon Katchalsky, later known as Aharon Katzir, was born in September 1913 in Łódź, Poland, according to Ynet; the National Library of Israel’s figures index gives his lifespan as 1913–1972.[1][2] His parents were Zila and Yehuda, and his younger brother Efraim later became Israel’s fourth president.[2] Other reference accounts differ on his birthplace and birth year: the Jewish Virtual Library gives 1914 and Łódź, while Encyclopedia.com gives 1913 and Kiev.[3][4]

The family immigrated to Eretz Israel in 1925 and settled in Jerusalem, according to Ynet, although the same account notes that some versions date their arrival to 1922.[2] The Jewish Virtual Library and a 1971 encyclopedia entry also report that Katzir was brought to Palestine in 1925.[3][5] Katzir attended the Hebrew Gymnasium in Jerusalem before pursuing higher education at the Hebrew University.[2]

He studied biology at the Hebrew University and completed a master’s degree in 1936 as part of the first graduating class of its Institute of Mathematics and Natural Sciences.[2] His studies also included chemistry, mathematics, and philosophy.[4] In 1936, he and naturalist Shimon (Fritz) Bodenheimer published a book introducing readers to the butterflies of the country.[2]

Katzir’s doctoral research examined polymers and reactions between the sugar aldose and protein molecules. He submitted his dissertation in late 1938 and received his doctorate in 1946, according to a 1971 biographical entry.[2][5] After his doctorate, he continued working in the Hebrew University laboratory for theoretical and macromolecular chemistry, where he had begun as an assistant.[2][4] He later taught at the university and became professor of physical chemistry in 1952.[3][4] In 1957, before traveling to a scientific conference in Moscow, he Hebraized his surname from Katchalsky to Katzir.[2]

Katzir’s scientific work sought to explain the molecular basis of life processes. His research ranged across polymers, muscle function, and the movement of substances through biological membranes, including passage into and out of cells.[4][2] He became known as a pioneer in the electrochemistry of biopolymers.[3]

In 1948, Chaim Weizmann invited Katzir to join the Weizmann Institute of Science. Katzir left the Hebrew University and founded the institute’s Department of Polymer Research, which he chaired until his death.[4][2] A contemporary encyclopedia entry described him as heading the polymer research department and chairing the institute’s Science Committee, positions it recorded as continuing in 1970.[5]

Katzir’s work on polyelectrolytes led him to investigate energy exchange, a field described in his biography as mechanochemistry.[4] His interest in thermodynamics also informed a mathematical approach to studying the permeability of biological membranes. He summarized this theory in Non-Equilibrium Thermodynamics in Biophysics; the biographical account says scientists worldwide adopted and applied it.[4]

His investigations of muscle activity explored how muscles convert chemical energy into mechanical energy. In the 1960s he built a machine that imitated this activity through the properties of protein fibers.[2] These lines of research linked his interest in macromolecules with broader questions about biological function and the physical processes underlying life.[4][2]

Katzir also sought to connect fundamental research with industrial application. In 1956 he established a plastics laboratory at the Weizmann Institute to develop new materials in close cooperation with industry.[2] Encyclopedia.com likewise describes him as establishing the institute’s Department of Plastics, with the stated aim of strengthening links between basic and industrial research.[4]

His scientific standing was recognized through major awards. Katzir and his brother Efraim jointly received the Weizmann Prize for Sciences in 1950.[2] In 1961, Katzir and his student Ora Kedem received the Israel Prize; sources identify it variously as the prize in chemistry and as an award in natural science.[4][2] He received other important prizes as well.[4]

Katzir combined scientific research with public and institutional service. He was among the founders of the Israel Academy of Sciences and Humanities, established in 1959. He became its vice president in 1960 and served as president from 1962 to 1968.[4][2] His leadership helped shape a national body for scientific work and scholarly exchange.[4]

His scientific responsibilities extended beyond universities. Katzir served on scientific committees of the Israel Defense Forces, on the board of the Defense Ministry’s Scientific Research Department, and on the government’s Science Advisory Council.[5][2] A 1971 encyclopedia entry records that he held the rank of lieutenant colonel in the IDF and served as president of the International Union of Pure and Applied Biophysics.[5] Ynet also describes him as president of the International Union for Biophysics and as an internationally connected scientist who helped link researchers in Israel and abroad.[2]

Katzir took part in efforts to expand Israel’s scientific and educational infrastructure. He played an active role in founding Ben-Gurion University of the Negev and worked to establish a university in Beersheba.[4][2] He also chaired the Standards Institution of Israel and advocated for an Israeli body devoted to space research.[2] His public work thus encompassed scientific governance, higher education, standards, and the organization of research.[2]

His involvement in national institutions began before the establishment of the state. Katzir joined the Haganah as a volunteer in 1930, while still a secondary-school student, and later held several roles, including command positions.[2] Encyclopedia.com describes him as a Haganah member and one of the founders of Hemed, identified there as the IDF’s scientific corps.[4]

After a research stay in Switzerland in 1947, Katzir discussed plans for a defense industry with Yaakov Dori, who was to become chief of staff of the Haganah. With David Ben-Gurion’s approval, he and Yehoshua Ratner reestablished the Haganah’s scientific department. The Haganah established the Science Corps in early 1948 as that department’s operational arm, and after Israel’s founding Katzir was appointed one of its commanders with the rank of lieutenant colonel.[2]

Katzir’s scientific work also served the pre-state community’s defense efforts. During World War II, he, Yeshayahu Leibowitz, and Moshe Brill published the 1943 booklet Scientific Innovations in War. It discussed military developments and civilian technologies relevant to military resilience, including blood transfusion, fuel production, and synthetic rubber.[2] Katzir and his brother also assisted the Haganah in weapons development.[2]

A later family account described Katzir producing potassium perchlorate for an explosive and helping prepare a projectile for the Davidka mortar.[6] After the war, Katzir advocated organized research planning and the development of a plastics industry in the Jewish community.[2] His public responsibilities therefore joined scientific institution-building with practical questions of defense and industrial capacity.[4][2]

Katzir devoted substantial effort to communicating science beyond specialist audiences. He wrote popular articles and books, lectured to general audiences, and was described as a gifted lecturer and one of the fathers of popular science in Israel.[4] His public-facing work reflected a conviction that scientific ideas could speak to wider social questions, not only to professional researchers.[2]

He initiated the radio program “World of Science,” and his lectures and broadcasts formed the basis of his 1971 book In the Crucible of the Scientific Revolution (also rendered in one account as The Crucible of Scientific Revolution).[4][2] The book addressed scientific and social questions and the points where they intersect.[2] Katzir also gave a Saturday-morning radio program, according to a recollection by his son Abraham, and sought to encourage young people to study important scientific fields.[6]

Accounts by his children portray him as a person of unusually broad intellectual interests. His son Gadi recalled that Katzir’s knowledge ranged across anthropology, zoology, physics, chemistry, and mathematics; his daughter Yael described him as a “Renaissance man.”[6] Encyclopedia.com similarly characterizes him as deeply involved in Israeli society and in practical matters including education and community action.[4]

Katzir’s public engagement also took the form of direct advice to political leaders. In 1956, when Prime Minister David Ben-Gurion was suffering from back spasms on the eve of the Sinai Campaign, Katzir recommended that he consult his colleague Moshe Feldenkrais, a physicist and judo expert whose ideas concerned orthopedics.[7] Feldenkrais examined Ben-Gurion, who was overseeing the campaign from his bed, and told him, “You will need seventy lessons.”[7] The episode illustrates Katzir’s ties to both scientific colleagues and the country’s public life.[7]

Alongside his research, Katzir participated in organized political and communal activity. He helped found and lead the Socialist Youth movement.[2] In 1939, at Ben-Gurion’s request, he coordinated youth protests in Jerusalem against the British White Paper, which included proposed restrictions on Jewish immigration and land purchase.[2]

His work for the Haganah developed alongside his academic career, from volunteering as a teenager to scientific and command roles connected with weapons development and the Science Corps.[2][6] His technical expertise, institutional responsibilities, and public engagement made him a prominent figure in the developing scientific community.[4][2]

Katzir was regarded as a possible candidate for Israel’s presidency. The Center for Israel Education says he was considered a candidate, while his daughter Yael recalled that representatives of Golda Meir and Yigal Allon approached him about the possibility roughly six months before his death.[8][6] After Katzir’s murder, his brother Efraim was elected Israel’s fourth president in 1973.[8][6]

Katzir was murdered on May 30, 1972, during the terrorist attack at Lod Airport, now identified in some accounts as Ben-Gurion Airport. He was waiting for his luggage when the attackers opened fire.[4] He was returning from a lecture tour or scientific conference in Europe, and accounts describe him arriving on an El Al flight.[9][2]

The Center for Israel Education reports that three Japanese Red Army attackers, working for the Popular Front for the Liberation of Palestine–External Operations, attacked the airport with machine guns and hand grenades.[8] A Jewish Virtual Library account says the three attackers were Japanese Red Army members recruited by the Popular Front for the Liberation of Palestine.[10] The Center for Israel Education reports that they arrived on an Air France flight from Rome with weapons concealed in violin cases, which attracted little attention from security officers looking for Arab terrorists.[8] Another account describes the cases as appearing to be violin cases and says the attackers opened them in the waiting area and removed assault rifles.[10]

The attackers killed 26 people and wounded 80, according to the Center for Israel Education and the Jewish Virtual Library.[8][10] Those killed included eight Israelis, one Canadian, and 17 Christian pilgrims from Puerto Rico.[8] Katzir was among the Israeli victims.[8] Accounts differ on the overall death and injury totals: Ynet’s biographical account reports 24 killed, including eight Israelis and 16 pilgrims from Puerto Rico, and does not give the same total as the accounts reporting 26 deaths and 80 wounded.[2][8] A 2017 Maariv report gives 25 killed, while a 2026 Ynetnews report gives 24 killed and 71 wounded.[11][9]

Sources also differ in their accounts of the attackers’ deaths. The Center for Israel Education says one attacker was fatally shot by a comrade, another died from his own grenade, and the third, Kozo Okamoto, was wounded and captured.[8] Katzir’s son Abraham later recalled that he did not know which of the three attackers killed his father.[9]

Katzir’s family was at the airport to meet him. A Maariv account reports that his son Abraham recalled running to find his father after the shooting ended and realizing that nothing more could be done.[6] A 2026 Ynetnews account, also drawing on Abraham’s recollections, says a flight attendant had directed Katzir to wait near the luggage rather than stand in line.[9] The National Library of Israel records Katzir’s lifespan as 1913–1972.[1] Accounts describe him as 58 or 59 at the time of his death.[6][12]

Katzir’s legacy rests on the combination of research, institution-building, public service, and science education. His work on polymers, biopolymers, mechanochemistry, and biological membranes contributed to research seeking to understand the molecular foundations of life.[3][4] His theoretical work on membrane permeability, as summarized in Non-Equilibrium Thermodynamics in Biophysics, was adopted and applied by scientists internationally, according to his biographical account.[4]

At the Weizmann Institute, the polymer department he founded and led and the plastics work he initiated embodied his effort to connect basic research to industrial development.[4][2] His role in establishing the Israel Academy of Sciences and Humanities, and his presidency of the academy from 1962 to 1968, placed him among the figures who helped organize scientific life in Israel.[4][2]

Katzir’s contributions extended into defense science, higher education, national standards, and international scientific cooperation.[5][2] He helped lay foundations for scientific and defense capabilities, in the assessment recalled by his son Gadi, and worked to encourage younger generations to pursue science.[6] His articles, lectures, broadcasts, and 1971 book brought scientific themes to public audiences.[4][2]

The National Library of Israel maintains an entry for Katzir in its Hebrew figures index and a separate entry for photographs of him.[1] His brother Efraim’s later election as president followed the loss of a scientist whom political leaders had considered for the same office.[8][6]

Biographical accounts disagree about Katzir’s birth year and birthplace. The Jewish Virtual Library gives 1914, while several other accounts give 1913 and an Aharon Katzir Prize page also gives 1914.[3][13] Accounts variously identify his birthplace as Łódź or Kiev.[3][4] Sources also differ on when his family arrived in Palestine: some give 1925, while Ynet notes accounts placing the move in 1922 and Maariv describes it as occurring in the early 1920s.[2][6]

Reports give totals of 24, 25, or 26 people killed in the Lod Airport attack and differing injury counts.[2][11] The Center for Israel Education and the Jewish Virtual Library report 26 killed and 80 wounded.[8][10] A 2026 Ynetnews report gives 24 killed and 71 wounded.[9] These differences are retained here as variations among the cited accounts rather than resolved beyond the evidence in the available sources.

A separate claim concerning Katzir’s scientific work was explicitly rejected by Ynet. The report says that Fusako Shigenobu claimed Katzir developed biological and chemical materials that killed Palestinians; Ynet characterizes the claim as false and states that Katzir did not develop biological or chemical weapons.[14]