The slideshow below guides students through instructions for building and programming a basic rolling robot. Students will modify this design in Activity 3 of the unit.

What force is acting on the robot to make it roll?

How does that force cause the robot to roll?

NGSS

Performance Expectations:

3-PS2-1.

Plan and conduct an investigation to provide evidence of the effects of balanced and unbalanced forces on the motion of an object. [Clarification Statement: Examples could include an unbalanced force on one side of a ball can make it start moving; and, balanced forces pushing on a box from both sides will not produce any motion at all.] [Assessment Boundary: Assessment is limited to one variable at a time: number, size, or direction of forces. Assessment does not include quantitative force size, only qualitative and relative. Assessment is limited to gravity being addressed as a force that pulls objects down.]

Disciplinary Core Ideas:

PS2.A: Forces and Motion

Each force acts on one particular object and has both strength and a direction. An object at rest typically has multiple forces acting on it, but they add to give zero net force on the object. Forces that do not sum to zero can cause changes in the object’s speed or direction of motion. (Boundary: Qualitative and conceptual, but not quantitative addition of forces are used at this level.)

Cross Cutting Concepts:

Cause and Effect

Cause and effect relationships are routinely identified.