The force of friction acts upon any moving object. The surfaces that are in contact with each other directly affect the frictional force that the object experiences. When the blocks are dragged across different surfaces, the force needed to keep the block moving varies from one surface to another. Adding masses on top of the blocks adds an additional variable for investigation.
The four surfaces are: cardboard, sandpaper (220 grit), cork, and vinyl. Required but not included are a spring scale and additional masses. Includes activity guide.