1.    The independent variable of this science fair project is the type of bearing used on the skate board. The dependent variable is the distance travelled by the skateboard from the ramp. This is determined  using a measuring tape. The constants (control variables) are the elevation of the ramp, the length of the ramp, the surface condition of the ramp and the floor surface. 2.    Purchase five different brands of skateboard bearings. Label them from A to E, from the  most costly to the least costly. An assumption is made that the bearing which is the most costly is manufactured .....