Eyes on Kepler laws: a multimedia based on data/images by a planetarium

“Eyes on Kepler Laws” has been realised on the basis of data and dynamic images from the Planetarium in Caserta (Italy) (scientific director L.A. Smaldone, http://www.planetariodicaserta.it). The three Kepler’s laws are addressed in the case of the planets of the solar system. The visualization of the planets’ motions, the surrounding stars and the Milky Way are based on real data and images. The polar projection (fish-eye format) allows to observe the full hemisphere of the sky. The time counters measure the time in Universal Time (U.T.). Pedagogical Effectiveness and Transformation Potential. These keywords summarise the educational contributions offered by “Eyes on Kepler Laws” in addressing some learning/teaching problems commonly encountered by students and teachers when the Kepler’s laws are studied (e.g. meaning of each law, similarities and differences in the planets’ orbits, evaluation of revolution periods, areal vs orbital velocity, etc.). Two historical portraits show Tycho Brahe (1546 – 1601) and Johannes Kepler (1571 – 1630) together with the first edition of Quadrans Muralis (1598) and Astronomia nova (1609), Harmonices Mundi (1619). These allude to the great power of abstraction of the work by Kepler, based on the analysis of very many and much accurate observations by Tycho Brahe. The connection between the orbits of the 8 planets in the solar system and their abstract representations as visualization of the orbits (dynamic display) can help the learners familiarise with these phenomena. The used planetarium images together with the possibilities of various viewpoints and scale changes (zooming in/out) produce a context very close to reality and much richer then that of a simulation based only on mathematical models. It is therefore possible to discuss power and limits of a model, approximations, graphic displays, etc… The Kepler First Law and the difficulty in understanding the different eccentricity of elliptical orbits is addressed by visualising Mercury, Venus and Earth orbits, the last two being almost circular while the first is clearly elliptical. The Second Law is clarified by analysing the motion of Mercury, with special focus on its position and velocity near perihelion and aphelion. The constancy of areal velocity can be checked be measuring the area swept off in four days of Mercury revolution (PM = 88 days). The Third Law is addressed via the examples of Mercury and Venus; the periods and semi-axes of their dynamically shown orbits are measured and related. The two planets move on the real background of a steady Milky Way and the moving Earth and Mars. The well acknowledged Predict – Observe - Explain (POE) learning cycle can be easily implemented. The learners are initially asked to predict features of the motion of various solar planets; then the multimedia is used and the learners explain, with their words (orally or in writing) the results of their observations. The comparison between the P and O phases of the cycle allows to address possible learning difficulties. Iteration of the POE cycle facilitate both spiralling around Kepler’s Laws and addressing their content at diverse depth. Eyes on Kepler Laws can be used for class activities, home work, tasks and problem-based learning. It is also appropriate in teacher’s education programs.