This activity shows students the engineering importance of understanding the laws of mechanical energy. More specifically, it demonstrates how potential energy can be converted to kinetic energy and back again. Given a pendulum height, students calculate and predict how fast the pendulum will swing by using the equations for potential and kinetic energy. The equations will be justified as students experimentally measure the speed of the pendulum and compare theory with reality.

Students explore how pendulums work and why they are useful in everyday applications. In a hands-on activity, they experiment with string length, pendulum weight and angle of release. In an associated literacy activity, students explore the mechanical concept of rhythm, based on the principle of oscillation, in a broader biological and cultural context in dance and sports, poetry and other literary forms, and communication in general.

What makes rockets fly straight? What makes rockets fly far? Why use water to make the rocket fly? Students are challenged to design and build rockets from two-liter plastic soda bottles that travel as far and straight as possible or stay aloft as long as possible. Guided by the steps of the engineering design process, students first watch a video that shows rocket launch failures and then participate in three teacher-led mini-activities with demos to explore key rocket design concepts: center of drag, center of mass, and momentum and impulse. Then the class tests four combinations of propellants (air, water) and center of mass (weight added fore or aft) to see how these variables affect rocket distance and hang time. From what they learn, student pairs create their own rockets from plastic bottles with cardboard fins and their choices of propellant and center of mass placement, which they test and refine before a culminating engineering field day competition. Teams design for maximum distance or hang time; adding a parachute is optional. Students learn that engineering failures during design and testing are just steps along the way to success.

Students are introduced to Newton's second law of motion: force = mass x acceleration. After a review of force, types of forces and Newton's first law, Newton's second law of motion is presented. Both the mathematical equation and physical examples are discussed, including Atwood's Machine to illustrate the principle. Students come to understand that an object's acceleration depends on its mass and the strength of the unbalanced force acting upon it. They also learn that Newton's second law is commonly used by engineers as they design machines, structures and products, everything from towers and bridges to bicycles, cribs and pinball machines. This lesson is the second in a series of three lessons that are intended to be taught as a unit.

In this activity, students use mathematics to understand tides and gravitation and how gravity works across astronomical distances, using an apparatus made from a slinky, meter stick, and a hook. A description of the mathematical relationships seen in the demonstration is included. The resource is from PUMAS - Practical Uses of Math and Science - a collection of brief examples created by scientists and engineers showing how math and science topics taught in K-12 classes have real world applications.

The purpose of this activity is to demonstrate Newton's 3rd Law of Motion, which is the physical law that governs thrust in aircraft. The students will do several activities that show that for every action there is an equal and opposite reaction.