Name ____________________________________ Date ___________ Period ________
Speed of the Bubble Lab
Purpose: In this lab investigation you will make a prediction about the speed of a rising bubble in three
colored tubes each with different viscosities. Using the formula Speed = Distance/Time you will
calculate the speed of the bubble in centimeters/second.
Hypothesis: _____________________________________________________________
_______________________________________________________________________
Materials: three bubble tubes; stopwatch; meter stick
Procedure:
1.) Measure the length of the tube and record the length in meters in the data table.
2.) Hold the first tube upright until the bubble reaches the top of the tube. Quickly flip the tube over
and start recording the time it takes for the bubble to rise to the top of the tube.
3.) Repeat your measurement 2 more times.
4.) Take the average of all your time measurements and record this number in the data table.
5.) Repeat steps 1 thru 4 for the other two tubes.
6.) Calculate the speed of the bubble as it rises up the tube using the formula R=D/T
Data Table:
Tube Color
Length
Time #1
Time #2
Time #3
Average
Time
Calculations:
Average Times
Tube #1
Tube #2
Tube #3
Speed of the Bubble R=D/T
Speed
Analysis Questions:
1.) In which colored tube did the bubble have the greatest speed? ______________________________
2.) In which tube did the bubble have the slowest speed? ____________________________________
3.) Give a reason why the speed of the bubble in each tube was different. _______________________
__________________________________________________________________________________
4.) If the viscosity (resistance to flow) was greater would the bubble rise faster or slower? __________
5.) Explain why the size of the bubble in the tube would change the speed of the bubble as is rises up
through the tube. ____________________________________________________________________
__________________________________________________________________________________
6.) Would the diameter of the tube affect the speed of the rising bubble? Why? ___________________
__________________________________________________________________________________
7.) How would the length of the tube affect the speed of the bubble? ___________________________
__________________________________________________________________________________
8.) If you tilted the tube at an angle what would happen to the speed of the bubble?________________
__________________________________________________________________________________
9.) Explain your answer to question #8 above. _____________________________________________
__________________________________________________________________________________
10.) What would the speed of the bubble be if the tube were laid flat on the table perpendicular to the
force of gravity? ____________________________________________________________________
11.) What force opposes the force of gravity and causes the bubble to rise upward in the tube when it
is tilted up?_________________________________________________________________________
12.) If the density of the fluid were greater what would happen to the speed of the bubble? _________
__________________________________________________________________________________
13.) Could the density of the fluid be increased enough, along with the viscosity, so that the bubble
would no longer be able to rise upward through the tube? ____________________________________
Typical Speed or Rate Problems:
1.) When playing football you run a straight line towards the goal. If you run 60 yards in 12 seconds
how many yards per second did you run?
2.) You drive from Los Angeles to San Francisco in 6 hours. It is a total of 390 miles one way. What
was your average speed during the trip?
3.) A plane flies from New York to Los Angeles in 6 hours. If the total distance traveled is 2100 miles
how fast was the plane flying?