Resumen: This paper describes a simple procedure for the study of the cooling of a spherical body, using a standard thermometer and a smartphone. For a more thorough analysis of the data, a computer can also be used. Experiments making use of smartphone sensors have been described before, contributing to an improved teaching of Classical Mechanics1-11, but rarely expand to Thermodynamics12-14. In this experiment, instead of using a smartphone camera to slow down a fast movement, we are using the device to speed up a slow process. For that we propose the use of FrameLapse free app15 to take periodic pictures (in the form of a time-lapse video) and then of VidAnalysis Free app16 to track the position of the mercury inside the thermometer, thus effortlessly monitoring the temperature of a cooling body Idioma: Inglés DOI: 10.1119/1.5018696 Año: 2018 Publicado en: PHYSICS TEACHER 56 (2018), 53-55 ISSN: 0031-921X Factor impacto JCR: 0.638 (2018) Categ. JCR: PHYSICS, MULTIDISCIPLINARY rank: 72 / 81 = 0.889 (2018) - Q4 - T3 Categ. JCR: EDUCATION, SCIENTIFIC DISCIPLINES rank: 37 / 41 = 0.902 (2018) - Q4 - T3 Financiación: info:eu-repo/grantAgreement/ES/DGA/UID/FIS/04564-2016 Tipo y forma: Article (Published version) Área (Departamento): Area Ingeniería Agroforestal (Dpto. CC.Agrar.y Medio Natural)