Marbles in Corn Syrup

Date: ______PAP IPC Name: ______

Measuring Motion of Falling Objects

Objective: To practice the following Science Skills: Predict; Measure; Record data; Calculate; Read a graph; Interpret data

Background Information

An object falling through air, or even water, moves too fast to measure accurately without sophisticated equipment. A medium that is thicker, or more viscous, than water slows an object down enough so that accurate measurements can be made. Although the rate of the motion depends upon the medium through which the object falls, the type of motion remains the same.

Prediction

Carefully read the investigation before stating your prediction. Remember to give the reasons for your prediction.

Materials 100- mL graduated cylinders or equivalent, pure corn syrup or 80 % corn syrup, marbles, stopwatch (or watch with second hand)

Procedure

1. Measure the distance (in cm) between each milliliter on the graduated cylinder. Record the distance here: 1 mL = ______cm

2. Fill the graduated cylinder to the 100-mL mark with the corn syrup at your desk.

3. One student should release the marble at the top of the corn syrup and should call out “0,” “2,” “4,” “6,” and so on, just as the marble reaches each EVEN milliliter markings. The second student should call out the total time elapsed in seconds or, if possible, fractions of a second each time the first student calls out the distance dropped. The third student should record these time values on a separate sheet of paper. These values will be used to fill in the Data Table after converting the mL to cm using the measurement in step one of this procedure.

For example: The group determined that 1 mL = 1.75 cm in step one. The time when “2” was called was 1.9 s. In the space after ‘0’ in the Data Table, the group should record 3.5 cm (1.75 x 2) for the distance traveled and 1.9 s for the time.

4. Use a new marble and repeat step 3.

6. Put the corn syrup back in the appropriately labeled bottle. Clean and dry the graduated cylinder and the marbles. If any syrup spilled on the table, clean the table also. Date: ______PAP IPC Name: ______

Data Table I

Distance Time (s) for Time (s) for Average Time (s) Traveled (cm) Trial One Trial Two for both Trials 0 0 0 0

Observations

Describe the motion you observed as the marble fell through the corn syrup.

Analysis

1. Use graph paper and a colored pencil to make a graph. The time is the independent variable. Plot the distance traveled, in centimeters, versus time elapsed, in seconds. Use your plotted points to make a ‘best-fit line.’

2. What kind(s) of motion did you observe as the marbles fell through the liquids.

2. What factors affect the marble’s motion? List as many as you can.

3. Imagine that you are an oceanographer. You are using a sophisticated sensing device that is dropped into the ocean and sinks like a rock to the ocean floor. On its way down, the device takes measurements every 5 seconds. You need to know what the depth is as each measurement is taken. Use the knowledge you have gained in this investigation to predict the motion of the falling device. 4. Complete Data Table II using the data you collected in the experiment for the first two columns and the calculated average velocity for the third column. You will need to use the average velocity equation given in the table. Notice that the “Distance” column is split. The numbers on the left side are to help you calculate the average velocity. These numbers are not data. See the example below.

For example: To calculate the first average velocity (line 2) you would take the distance in line 2 minus the distance in line 1 and divide by the time in line 2 minus the time in line 1. The next average velocity (line 3) would be calculated by taking the distance in line 3 minus the distance in line 2 and dividing by the time in line 3 minus the time in line 2. The next average velocity (line 4) would be calculated by taking the distance in line 4 minus the distance in line 3 and dividing by the time in line 4 minus the time in line 3. Continue in this manner until the table is complete.

Data Table II

Distance Traveled (m) Average Time (s) Average Velocity (cm/s) (From Data Table I) (From Data Table I)  d    t 1 0 0 0 2 3 4 5 6 7 8 9 10 11 12 13 14 15

5. Prepare a graph of the data in Data Table II. (The time is the independent variable and the VELOCITY, not distance, will be the dependent variable. Distance will NOT be plotted on this graph.)

Note: You may put both of the graphs required for this lab on the same piece of graph paper if you can write on both sides of the graph paper. Do NOT use one side of the graph paper for both graphs. Make certain your name is on all pages turned in.