Science practice 75

PASSAGE IV

A group of students conducted several experiments using a variety of nonstick cookware, a spring scale, and several objects with different mass. Their goal was to determine which brand of cookware products had the best nonstick surface by measuring the coefficient of static friction, which is a measure of how resistant a stationary object is to movement.

Experiment 1

A student connected the spring scale to a weighted object that was placed inside a piece of nonstick cookware as shown in Figure 1.

Figure 1

The students planned to calculate the coefficient of static friction by determining the force required to disturb an object from rest. During the experiment, one student anchored the nonstick cookware by holding tightly to the handle while the other student attached a weighted, smooth steel object to the spring scale. The student pulled on the spring until the object began to move. A third student recorded the force in newtons, N, indicated on the spring scale at the moment the object began to move across the nonstick surface.

This procedure was repeated for 3 different brands of cookware; each brand of cookware was tested with various weighted objects. The coefficient of static friction was calculated and the results are shown in Table 1.

Experiment 2

The students performed an experiment similar to Experiment 1, except three different brands of cooking spray were applied to the same cookware surface before the weights were put in place. The results are shown in Table 2.