During the early decades of the 18th century, Newtonian physics was still new. Much effort was expended in testing its validity. One arena in which evidence could be found was the shape of Earth. Was it perfectly spherical? On the observational side there were two hints. In 1671 Jean Richer had measured the rate of ticking of a pendulum clock near…

In this work we describe a teaching proposal to calculate the eccentricity of the Moon's trajectory by applying a geometrical technique. The values of the ratios between the Earth-Moon distance and the diameter of the Moon at apogee and at perigee were calculated from a kinematic model associated with a geometrical technique of image analysis. The…

Most students know that planetary orbits, including Earth's, are elliptical; that is Kepler's first law, and it is found in many science textbooks. But quite a few are mistaken about the details, thinking that the orbit is very eccentric, or that this effect is somehow responsible for the seasons. In fact, the Earth's orbital eccentricity is…

November 10, 2015, marked the 40th anniversary of the sinking of the "S. S. Edmund Fitzgerald," a Great Lakes bulk cargo freighter that suddenly and mysteriously sank during a severe winter storm on Lake Superior. A year after the sinking, Canadian folksinger Gordon Lightfoot wrote and recorded the ballad "The Wreck of the 'Edmund…

Simulations of physical systems are widely available online, with no cost, and are ready to be used in our classrooms. Such simulations offer an accessible tool that can be used for a range of interactive learning activities. The Jovian Moons Apple allows the user to track the position of Jupiter's four Galilean moons with a variety of…

Heat transfer is widely taught in secondary Earth science and physics. Researchers have identified many misconceptions related to heat and temperature. These misconceptions primarily stem from hunches developed in everyday life (though the confusions in terminology often worsen them). Interactive computer simulations that visualize thermal energy,…

Presents a mathematical explanation for the development of tidal activity. (MVL)

This article describes a teaching aid made from four colored foam balls mounted on a stiff wire circle used to teach about the changing seasons and earth temperature fluctuations. The spheres represent the Earth at the solstice and equinox positions. (MVL)

Describes a method for determining the distance to the horizon which leads to determining the radius of the Earth. The article answers two interesting science questions: (1) Can you see the state of Kansas from Pike's Peak in Colorado? and (2) Can you see two sunsets in one day on the Keys of Florida? (MVL)