Investigating the Velocity of a Sinking Marble
In this lab, you will graph the motion of a marble falling through shampoo.
Problem What does a distance-time graph look like for a marble falling through shampoo?
Materials
clear shampoo
100-mL graduated cylinder
2 small marbles
stopwatch
forceps
masking tape
metric ruler
10-mL graduated cylinder
long glass stirring rod
dropper pipet
graph paper
Skills Measuring, Observing, Using Tables and Graphs
Procedure
On a separate sheet of paper, make a copy of the data table shown.
Wrap a small amount of masking tape around the tips of the forceps. This will allow you to grip the marble with them.
Measure the distance between the 10-mL gradations on the 100-mL graduated cylinder. Record the new distance in the first row of your data table.
Multiply this distance by 2 and write the result in the second row. For the third row, multiply the distance by 3. Continue until you have written distances in 10 rows.
Slowly pour 100 mL of clear shampoo into the 100-mL graduated cylinder.
Be ready to observe the marble as it falls through the shampoo. Grasp the marble with the forceps and hold the marble just above the shampoo-filled graduated cylinder.
Say “Go!” as you drop the marble into the shampoo. At the same moment, your partner should start the stopwatch.
Each time the lower edge of the marble reaches a 10-mL mark on the cylinder, say “Now.” Your partner should note and record the time on the stopwatch.
Continue calling out “Now” each time the marble reaches a 10-mL mark until it comes to rest on the bottom of the cylinder. Say “Stop!”
Use the 10-mL graduated cylinder to add about 8 mL of water to the 100-mL graduated cylinder. Use the glass stirring rod to mix the water and shampoo gently but thoroughly.
With the dropper pipet, remove enough liquid from the graduated cylinder to decrease the volume to 100 mL.
Repeat Steps 6 through 9 using another marble.
Wash all supplies as instructed by your teacher.
Analyze and Conclude
Using Tables and Graphs Use the data you collected to make a distance-time graph for each of the two marbles.
Observing Explain the motion of the marbles as they fell through the shampoo. How did you show this motion on your graphs?
Inferring Based on your graphs, were the marbles accelerating? Explain your answers.
Calculating Use your data table to calculate the average speed of each marble.