Students will construct simple Lego™ cars, and, by attaching them to Spheros, investigate how increasing and decreasing the amount of force applied affects them. Students can program varying speeds in order to increase and decrease the force. They may also try pushing and pulling different objects. Students should collaboratively select the surfaces they wish to test (e.g., asphalt, cardboard, carpet, cotton towel, crushed stone, grass, sandpaper, tile floor, wood) and decide how different surfaces affect the amount of force needed to keep Sphero in motion, and predict which surfaces will require the most and least force and provide explanations for the prediction. Collaboratively, students would devise a procedure, identify required materials and measuring instruments to fairly test each surface, and carry out their procedure to ensure a fair test, while taking repeated measurements of the force needed to move the Sphero. Students record measurements in a table, compare results, and provide explanations for any patterns or discrepancies noted; and draw a conclusion, ordering the surfaces from least to greatest according to the amount of force required to move the Spheros at a constant rate of motion. Students should relate their findings to the effect of friction.