INTRODUCTION - READ AND FILL THE BLANK FOR FULL CREDITS.

The rate at which a marble falls through corn syrup depends upon the viscosity, or thickness, of the syrup. 
In this investigation, you will allow a marble to fall through syrup solutions at three different concentrations 
(hence, three different viscosities). You will measure the speed at which the marble falls in each solution and pay 
particular attention to the question of whither the marble's speed is always changing as it falls or if its speed remains 
constant during part or all of the fall. You will graph your results to aid your analysis.

MATERIALS:

3 100-mL graduated cylinders	Stopwatch or watch that indicates seconds.
glass marbles	100 mL of 80% solution of corn syrup in water
marking pencil	100 mL of 90% solution of corn syrup in water
meter stick or tape	100 mL of pure corn syrup
graph paper	250-mL beaker
pencils or pens of 3 different colors







PURPOSE:

to graph the speed of marbles falling through different solutions of corn syrup and to construct and interpret distance-time graphs.

PROCEDURE:

1. fill a 100-mL graduated cylinder with a 80% solution of corn syrup in water and label it #1. Fill a second cylinder with a 90% solution of corn syrup in water and label it #2. Fill a third cylinder with pure corn syrup and label it #3.

2. Starting with the level of the liquid, make marks 2 cm apart down the length of each cylinder with a marking pencil. Number the marks, starting with zero at the top.

3. In a first trial, time the fall of a glass marble in Liquid #1. Use the bottom edge of the ball for reference. In DATA TABLE 1, record the time the marble passes each mark. 

Remember: the time is continuous running time for the entire trial.

4. Remove the marble for a second trial by pouring the liquid into a beaker. Rinse and dry the marble. Return the liquid to the graduated cylinder and repeat the trial.

5. Repeat Steps 3 and 4 using the other two liquids. Record your data on the appropriate data table.

DATA TABLE 1: Marble in Liquid #1.
	Travel Time (s)
Distance Traveled (cm)	Trial 1	Trial 2
0	0	0
2
4
6
8
10
12
14

DATA TABLE 2: Marble in Liquid #2.
	Travel Time (s)
Distance Traveled (cm)	Trial 1	Trial 2
0	0	0
2
4
6
8
10
12
14

DATA TABLE 3: Marble in Liquid #3.
	Travel Time (s)
Distance Traveled (cm)	Trial 1	Trial 2
0	0	0
2
4
6
8
10
12
14

6. Use graph paper to prepare a graph of the results of the second trial in each liquid. Plot the distance traveled on the vertical axis and time on the horizontal axis.Use the same graph for all three liquids. Use different colors to identify the data points for the different liquids. Draw a smooth line through each set of data points. Be sure to label each line as to which solution it represents.

QUESTIONS:

1. Compare the three graph lines. What part of a line indicates constant speed? In which of the liquids did the marble reach a constant speed?

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2. Which graph line indicates the greatest speed? In which of the liquids did the marble reach the greatest speed?

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CONCLUSION:

For each liquid, describe whither the speed of the marble increased, decreased, or stayed the same as the marble moved downward.

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