# Science in Focus:Force and Motion

### A video workshop on the mechanics of force and motion for K-8 teachers

Explore science concepts in force and motion and come away with a deeper understanding that will help you engage your students in their own explorations. With science and education experts as your guides, learn more about gravity, friction, air resistance, magnetism, and tension through activities, discussions, and demonstrations. Extensive footage shot in real classrooms shows students learning and building on ideas as they explore the relationships among motion, force, size, mass, and speed. As you watch the students develop understanding through activities that connect science concepts to real-world phenomena, you will be asked to think about your own ideas on force and motion and compare them to what you observe.

Program guides and supporting materials (PDF)

Produced by the Smithsonian Institution Astrophysical Observatory
with support from Annenberg Learner (2001)

Workshop 1. Making an Impact
What would happen if an asteroid were to hit the surface of the earth? How large a crater would the impact create? In this workshop, the ideas of force and motion are introduced, as seventh-grade students drop balls to simulate asteroid impacts. By varying a ball's mass, the height from which it is dropped, or the material being struck, the students explore what factors affect the size of the crater. They also learn about data collection and the proper use of measurement units.
Workshop 2. Drag Races
Forces can help put objects into motion and can also bring moving objects to a stop. In this workshop, fifth-grade students explore the physics of motion using plastic cars with strings and washers attached to provide a pulling force. The students test the speed of the vehicles and explain what forces bring the vehicles to a stop, as the cars collide with and displace barriers at the end of their run. Finally, the students discuss their findings to help solidify their understanding of the effect of forces on motion.
Workshop 3. When Rubber Meets the Road
A rubber band twisted around the axle of a plastic car provides the force that moves the car forward. In this workshop, fifth-grade students continue their exploration of force and motion by recording and comparing the distance a vehicle travels under various conditions. Students predict the distance the car will travel by counting the number of twists in the rubber band, and observe the car's speed as it rolls across the floor. When the force of the rubber band stops acting, the force of friction slows the car to a stop.
Workshop 4. On a Roll
The force of gravity makes a ball roll when it is placed on an incline. In this workshop, first-grade students roll balls of different sizes, masses, and materials down ramps of varying heights, comparing their speeds. The students then experiment by replacing the ramp with a cardboard tube, and try to determine how the tube must be oriented to allow the ball to roll, much as it rolled down the ramp.
Workshop 5. Keep On Rolling
Roller coasters are filled with twists and turns, as changes in height and direction supply a variety of push and pull forces. In this workshop, first-grade students build on their prior experience with rolling objects. By designing and constructing their own roller coaster made from ramps, cardboard tubes, and flexible tubes, the students experiment with ways to get a marble from the top of a table into a bucket on the floor, some distance away.
Workshop 6. Force Against Force
Magnets stick to other magnets and to metal objects made of iron or steel. How much force is required to break the attraction between two magnets? In this workshop, fourth-grade students explore ways to balance the force of magnetism against the force of gravity. A magnet placed in a cup on one side of a pan-balance is stuck to a stationary magnet beneath the cup. When enough washers are placed on the opposite side of the balance, the magnets will separate. Graphical analysis shows some unexpected results.
Workshop 7. The Lure of Magnetism
What is the difference between a permanent magnet and an electromagnet? In this workshop, fourth-grade students build an electromagnet by winding a wire around a rivet and attaching the ends to battery terminals. The students first predict how many washers they can pick up with the help of their electromagnet and then perform the experiment to test their predictions. After the number of washers is recorded and the results are discussed, the students engage in a group discussion about practical uses for electromagnets.
Workshop 8. Bend and Stretch
We all expect a spring to stretch or compress when a force is applied, but forces can even deform solid objects like the floor or the top of a table. In this workshop, students in a high school classroom explore ideas about tension and normal force. By applying a force to a spring and measuring the distance the spring is stretched, the students calculate the force constant or stretchiness of the spring. Lecture demonstrations using student volunteers help to illustrate that even rigid objects bend when a force is applied.