Describes an experiment demonstrating Lenz's law by measuring a magnet falling through a copper tube compared to a nonmagnet falling. Presents diagrams and pictures showing the apparatus. (YP)

Presents the theoretical explanation of the observation that when a pen that is stuck in a hard rubber ball and dropped, the pen may bounce to several times the dropped height. Includes the procedure and models created to explain the observations. (DS)

Describes three experiments with an air table to produce a centripetal force. Provides some diagrams and pictures of the apparatus. (YP)

Introduces a computer solution of the oscillation of a mass suspended by a spring in a viscous liquid. Describes the equations of motion, spreadsheet solution, copying the formulas, plotting the results, and extending the applications. Presents spreadsheet and physics formulas for the step-by-step solution and spreadsheet solution. (YP)

Presents an experiment to show the energy conservation principle using a bow. Describes how to measure the force and work of the bow and the initial velocity of an arrow. (YP)

Shows the difficulties of understanding the hypothesis a posteriori. Describes a scientific method containing phenomenologic, hypothetic, and theoretic phases. Provides the results of an experiment on simple pendulum oscillation by using this method. (YP)