The test variable (independent variable) is the one factor you are changing from trial to trial. The outcome variable (dependent variable) is what changes as a result (the data you collect). Record these on your lab report. Write your hypothesis statement on your lab report. A hypothesis should follow an if/then statement using the variables. How do you think your test variable (independent variable) will affect your outcome variable (dependent variable)? If (test variable changes this way), then (outcome variable will change this way). Gather the materials to conduct your trials. Stack two books or blocks on top of each other. Lay the board or notebook at an angle from the top of the stack to the floor to form a ramp. board proped up on two books You will be testing three different flooring surfaces to determine how the texture of the surface affects the distance the ball will roll. For each one, you will conduct three trials on each surface. To prepare for each set of three trials, change the surface of the ground at the bottom of the ramp. For example, the first set of three trials might be conducted on a flat concrete surface. The next set of three trials may be conducted on carpeting, or with a towel lying at the bottom of the ramp. Be sure each set of trials is conducted with a different type of surface at the bottom of the ramp, so you are testing the question given in the purpose of the experiment. board proped up on two books with extended surface at the bottom of the other end Be sure to start each trial by placing the ball at the center of the top of the ramp and then releasing it. Important: Do not push the ball down the ramp, because you need to make sure the ball travels at the same rate for each trial. ball sitting at top of a board that is propped up on one end with two books Release the ball from the top of the ramp and allow it to roll along the surface of the ground until it stops. Mark the place where the ball stopped, and measure the distance from the bottom of the ramp to the "back" of the ball. Record this measurement in centimeters. ball rolled down extended surface of proped up board stating distance traveled Repeat steps 5 and 6 two more times, for a total of three trials, for each ground covering. Be sure to test at least three different ground coverings in this experiment. Record all measurements on your lab report.