Alkane Viscosity Experiment
Viscosity of Alkanes Experiment
• First Experiment:
– Measured viscosity using marble drop
– Timed from 80 mL to 30 mL
– Problems?
• Timing difficult (marble too fast)
• Marble may have variable weight
• Others?
• Further Experiments:
– More reliable timing data
– Determine the effect of marble mass on data
collection
Alkane Viscosity
• Further Experiments:
– More reliable timing data
• Measure time over longer distance (100 mL?)
• Perform more trials to ensure consistency and
discard outlying data
– Determine the effect of marble mass on data
collection
• Perform trials of 1 oil using different marbles to
ensure that data collection is unaffected
• Provides evidence to defend experimental setup
when presenting findings
Alkane Viscosity
• Three additional experiments
1. Re-do previous experiment with 100 mL
distance
2. Perform marble drop with 1 oil, using 5
different marbles (mass each first) at 3 trials
each
3. Determine density of each oil to establish a
correlation (or lack thereof) between density
and viscosity
Alkane Viscosity Report
• Data Tables (typed) of all collected data for all
experiments
– 50 mL drop experiment, 9 oils x 3 trials each (+ avg.
time for each = 36 data points)
– 100 mL drop expt, 9 oils x 3 trials each (+ avg. time
for each = 36 data points)
– Marble mass expt, 5 marbles x 3 trials each (1 oil
for total of 20 data points)
– Density, 6 oils (expressed as g/mL)
• Make sure that tables are clearly labeled and
organized logically
Alkane Viscosity Report
• Graphs
1. 50 mL drop: graph average drop time for
each oil
2. 100 mL drop: graph avg. drop time for each
oil
3. Superimpose both graphs with different
colors for each line (double 50 mL data)
4. Marble mass: graph average time for each
marble
5. Density: graph density for each oil
6. Graph density vs. 100 mL drop time
Analysis
• After creating tables and graphs, analyze
available data
• Possible questions to consider:
– Was the 100 mL drop data more reliable than the
50 mL drop? How can you tell?
– Does the mass of the marble affect drop time? Is
it significant enough to alter our experimental
design?
– Is there a correlation between oil density and
viscosity (i.e. drop time)?
– If density does not explain viscosity, then what
other experiments could be done in the future?
– Consider other questions…what does the data
indicate? What does it NOT indicate?
Lab Report Write-Up
• Organized tables and graphs
• Analysis section
• Error Analysis
– What were problems with the experimental
design?
– For what variables have we NOT accounted?
– In collecting your data, what errors may have
occurred?
– How reliable is your data?
Scoring
• Your grade for the write-up will be
determined by the following factors
– Organization and clarity
– Logical flow to analysis/error analysis
• Don’t answer each question individually
• The answers should all be presented together as
part of your overall analysis
– Thorough consideration of questions in
analysis and error analysis sections
– Consideration of other factors/questions