Earth Science Regents
Performance Test Bead Drop:
“Settling it once and for all!”
Bead Drop Research Team SUNY Oneonta
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Dr. Jim Ebert, Earth Sciences Dept.
Ron Chapin
Trish Emmons
Don Zaengle
Gerald Jones
Tom Sansone
Student Participants
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Student participants in the Station 5
research project were Secondary
Education/Earth Science Students
enrolled in ESCI 315: Laboratory
Techniques in Earth Science in the
Spring semesters of 1999 and 2000
Variables investigated in 1999
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Variation in bead density with
temperature
Variation in fluid density with
temperature
Changing time to terminal velocity with
fluid height in column
Variation in fluid viscosity with
temperature
Research in 2000
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Focus on viscosity change with
temperature
Construct correction curves?
Examine other fluids with less
temperature-dependent viscosity
Let’s drop some Beads!!
ESCI 315 data for Red Beads
30
25
20
15
10
5
0
Veg Oil (n=92)
Temperature (C)
32
30
28
27
26
25
24
23
All (n=91)
22
21
Settling Time (sec)
4 mm Beads
Temperature vs Settling Time
ESCI 315 data - Green Beads
6 mm Beads
Temperature vs Settling Time
Veg Oil (n=99)
All (n=84)
10
5
Tem perature (C)
32
30
28
27
26
25
24
23
22
0
21
Settling Tim e (sec)
15
ESCI 315 data – Orange
Beads
8mm Beads
Temperature vs Settling Time
Veg Oil (n=91)
8
All (n=89)
6
4
2
Tem perature (C)
32
30
28
27
26
25
24
23
22
0
21
Settling Tim e (sec)
10
Settling Time –
expanded scale
Settling Time (sec)
8mm Beads - Veg. Oil Solution
Temperature vs Settling Time
4
3
n=91
2
21 22 23 24 25 26 27 28 30 32
Temperature (C)
Settling Time –
expanded scale
4mm Beads - Veg. Oil Solution
Temperature vs Settling Time
9
n=92
8
7
Temperture (C)
32
30
28
27
26
25
24
23
22
6
21
Settling Time (sec)
10
Range of settling times
with temperature
Time (sec)
4 mm Beads
Temperature vs Settling Time
Raw Data
30
25
20
15
10
5
0
Veg Oil (n=92)
All (n=91)
Temperature (C)
Viscosity and settling time
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Water-based solutions show significant
changes in viscosity with changes in
temperature
Settling time may vary by up to 50% over
range of typical classroom temperatures
Vegetable oil shows very slight changes in
viscosity and therefore settling time with
changes in temperature
“Channeling”
and water-based solutions
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Water-based solutions displayed an
unexpected “channeling” effect
A visible “channel” was observed in the fluid
column
Beads entering this channel settled
significantly faster than beads outside the
channel
Settling times in water-based solutions may
vary by up to 6 seconds at a single
temperature!
CONCLUSIONS
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Use Vegetable Oil for Station 5
Viscosity and therefore settling time is
less affected by temperature during
administration of the practical
With vegetable oil, it should be possible
to make up a single key for each set-up
and not have different keys for different
times of day/temperatures.
Helpful hints for Station 5
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USE VEGETABLE OIL instead of water-based
solutions. Oil is less susceptible to
temperature-induced changes in viscosity.
Therefore there will be less “drift” in settling
time. Also, “channeling” is not a problem.
Be aware that settling times in oil are faster
than water-based solutions. Adjust timing
marks on columns to give appropriate settling
times.
Helpful hints for Station 5
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Use Number 7 or 8 rubber stoppers in
the bottoms of columns. They give a
better seal than the plastic fittings.
Place the bottom of the tube in a plastic
beaker or whipped topping container to
ease clean-up in the case of minor
leaks.
Helpful hints for Station 5
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Place a film-cannister
“bailer” at the bottom of
the tube to retrieve
beads. Holes in the
cannister allow fluid to
drain out.
Bent pieces of coat
hanger are good for the
“hook” and straightened
coat hangers work well
to retrieve the bailer.
Thanks to Irv Soden for
this suggestion.
Helpful Hints for Station 5
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Plastic petri (culture) dishes work well
for holding the beads at each station.
Use masking tape to anchor the dishes
to the table top to minimize the chances
of students spilling beads (of course,
this NEVER happens!)
Helpful Hints for Station 5
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Glue beads onto the station directions so
that there is no ambiguity over which
beads the students should use for each
trial.
Use plastic page protectors for the station
instructions. This prevents students from
writing on them, shields them from spills
and preserves them for future use.
CLEAN UP
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Hot soapy water works well for
removing oil from beads, tubes and
stoppers. You can even use the
detergent from previous years!
Oil can be kept in the original bottles
indefinitely.