Viscosity is the resistance of a fluid to flow. Both liquids and gases are considered fluids. A viscous fluid has a high viscosity. That is, it does not flow easily. A less viscous fluid flows more easily. Students studying viscosity filled three test tubes with liquids: syrup, water, and baby oil. In each test tube there was an air bubble and as the students tilted the tubes, the bubbles moved. To calculate the speed of the bubble in the liquids, students measured the height of the liquid in each tube: height = distance bubble travels. The students inverted the test tubes and measured the time it took for the air bubble to move from one end to the other through the fluid. They repeated this procedure five times and calculated average speed of the bubble.
Data Table
Tube A Tube B Tube C
Distance
(cm) Time
(s) Speed
(d/t) Distance
(cm) Time
(s) Speed
(d/t) Distance
(cm) Time
(s) Speed
(d/t)
15.6 35 .45 15.4 1.5 10.27 15.6 2.6 6.0
15.6 36 .43 15.4 2 7.7 15.6 3.0 5.2
15.6 35 .45 15.4 2 7.7 15.6 2.8 5.6
15.6 37 .42 15.4 2 7.7 15.6 2.6 6.0
15.6 36 .43 15.4 1.5 10.27 15.6 2.6 6.0
Average Speed .44 Average Speed 8.73 Average Speed 5.76
1)
One group hypothesized that the liquid in test tube A was syrup. What rationale was used to construct this hypothesis? Did the student data support the hypothesis?
A) The speed of the bubble in test tube A was the slowest but that does not confirm that it is syrup.
B) If syrup is the most viscous, the speed of the bubble will be the slowest. The data shows that the speed of the bubble is slowest in test tube C, so that must be syrup.
C) If the air bubble in test tube A had the slowest speed then the liquid is syrup. Syrup is the most viscous liquid. Yes, the data shows the air bubble with the slowest speed is in A.
D) Because syrup is thick, it is the most viscous and we would expect the air bubble to have the slowest speed in the test tube containing syrup. No, the slowest speed is in test tube B.
2)
Consider the data collected by the three groups. Based on the prompt, how would you categorize the results of the first group, A, compared to the other groups, B and C? All BUT ONE answer choice can be verified.
A) The students in group A provided the most consistent data collected.
B) The students collected the data more carefully than the other groups.
C) The experiment can be repeated to conform the data that was collected.
D) It is the most reliable set of data of the three sets of data collected.