One of the essences of scientific exploration lies in the "controlled variable method"—changing only one factor in an experiment while keeping all other conditions constant to observe the effect of that single factor. The quantitative relationship of Newton's Second Law is an excellent subject for verifying using this method. Our exhibit cleverly guides you to play the role of a researcher: you are presented with two almost identical motion systems (a cart and a track). Your task is to first let them move under standard conditions, observe their consistent speed performance, and establish a "baseline." Then, you are guided to make a single crucial intervention: adding weight to one of the carts, changing only the variable of "mass" while striving to keep the variable of "tension" constant. When you restart the experiment, the difference in the motion performance of the two carts can be clearly and uniquely attributed to the change in "mass." This "cause-effect" connection established t
