Resumen: All general physics textbooks include a chapter regarding hydrostatics. Archimedes’ and Pascal’s principles are commonly covered, but surface tension is merely named. Few people knows that surface tension contributes to the buoyancy of any object, with more or less relevance.1 I think that including surface tension in general physics courses is important to understand all phenomena regarding hydrostatics, and this is why every year, before starting the lesson regarding hydrostatics, I pose a question to the students: Can 1 kg of iron float on water? Usually, some of them answer instinctively, saying, “no, that is not possible.” Others, knowing that I am used to showing them physics “tricks” in the classroom, remain thoughtful. Anyway, it is a question that would be answered negatively by around 90% of questioned people. However, as I will show, there are at least two ways to make 1 kg of iron float. Idioma: Inglés DOI: 10.1119/5.0097946 Año: 2023 Publicado en: PHYSICS TEACHER 61, 8 (2023), 644-645 ISSN: 0031-921X Factor impacto JCR: 0.5 (2023) Categ. JCR: PHYSICS, MULTIDISCIPLINARY rank: 93 / 112 = 0.83 (2023) - Q4 - T3 Categ. JCR: EDUCATION, SCIENTIFIC DISCIPLINES rank: 72 / 86 = 0.837 (2023) - Q4 - T3 Factor impacto CITESCORE: 1.1 - Education (Q3) - Physics and Astronomy (all) (Q4)