Transcript Liquid Conductivity - Welcome to Educational Equity

Liquid Conductivity
The creating and testing of a
conductivity meter.
TEAM I
Pedro Guerrero
Roc-Quelle Barksdale
Jamia Pugh
INTRODUCTION
• Conductivity measures a
materials ability to
conduct an electrical
current. Its measured in
µS/cm
• Conductivity is used to
measure the amount of
total dissolved solids
(TDS) in water
• Environmental Protection
Agency (EPA) limits a
maximum of 500ppm of
TDS for drinking water.
Making our Conductivity Meter
We built our own conductivity meter.
•Our meter: under $50
•Store bought: around $450
•Our meter is cheaper and portable.
A
B
Vernier Meter- $450
A
Our Meter- $50
B
Our purpose was to build an inexpensive, portable, working conductivity
meter, without the expensive price. Our meter is 1/9 the price of a store
bought meter!
Testing Our Meters…
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
y = 180.51x + 0.0903
R² = 0.9971
y = 83.652x + 0.0392
R² = 0.9949
NaCl
CaCl2
y = 68.284x + 0.018
R² = 0.9995
0
0.002
0.004
0.006
0.008
Salt Concentration (M)
0.01
AlCl3
0.012
Carlos and Pedro
1.8
Conductivity Meter Reading (V)
Conductivity of pure water = 0
Things that affect conductivity
 Ion Concentration
A molecule does not have
same amount of protons
as electrons, giving it a
positive or negative charge.
Conductivity Meter Reading (V)
Jamia and Roc-Quelle
y = 154.81x + 0.1117
R² = 0.9888
1.6
1.4
1.2
y = 85.568x + 0.0226
R² = 0.998
1
NaCl
0.8
CaCl2
0.6
y = 66.495x + 0.0133
R² = 0.9989
0.4
0.2
0
0
0.002
0.004
0.006
0.008
Salt Concentration (M)
0.01
0.012
AlCl3
Ion Concentration Affects
Conductivity
NaCl
CaCl2
AlCl3
Temperature affects the conductivity.
When temperature increases, conductivity
increases.
Conductivity Reading (V)
0.8
y = 0.0067x + 0.1215
R² = 0.9948
Conductivity Meter Reading
(V)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
10
20
30
40
50
Temperature (°C)
60
70
80
90
WATER QUALITY
• Samples of water were collected around
the Penn State area and were tested with
our conductivity meters
• We took a field trip to the following water
sources:
Because our devices were portable
• Whipple Dam
Spring Creek
Shavers Creek
RESULTS……….
Conductivity Reading In the Field
0.23
0.264
0.3
Conductivity Meter Reading (V)
Conductivity Meter Reading (V)
0.25
0.2
0.25
0.15
0.043
0.05
0.015
0.02
Shavers
Creek2
Whipple
Whipple
Dam
Dam
Upper
Lower
Water location
0.1
0.078
0.042
0.022
0.05
0
Shavers
Creek 1
0.2
0.15
0.083
0.1
A
In Lab Conductivity Reading
Spring
Creek
0.023
0
B
Shavers
Creek 1
Shavers
Creek 2
Whipple Whipple
Dam
Dam
Upper
Lower
Water Location
Spring
Creek
Calculating TDS
• Conductivity can be calculated from the
reading on our meters using Ohm’s Law.
• We calculated Spring Creek to have a
conductivity of 533µS/cm.
• Then, by multiplying the conductivity by
0.75, then you can calculate total
dissolved solids.
• This means the TDS is 400ppm. Below
EPA ‘s limit.
BRITA FILTER
• Every Brita Filter contains charcoal and
ion exchange resin (zeolites).
• Charcoal is used to remove the chlorine
ions and some organic compounds.
• Zeolites are used to remove metal cations
copper, zinc, mercury, and cadmium.
A
B
TESTING
To test the zeolites and charcoal, we used an
aluminum chloride solution.
Brita Filter
Conductivity Meter Reading (v)
0.6
0.59
0.58
0.56
0.55
0.54
0.52
0.52
0.5
0.5
0.48
0.46
0.44
AlCl3
AlCl3 (charcoal)
AlCl3 (zeolites)
Solutions Tested
AlCl3 (both)
Conclusion
•
We built an inexpensive, portable,
working conductivity meter.
• The meter is a good tool to use when
trying to see if certain types of water
meets EPA standards.
• It can also be used in high school labs
because of the low cost and portability.
Special Thanks to…
• Eberly College of Science
• Dr. Jackie Bortiatynski
• Dr. Dan Sykes
• Jody Markley
• Derek James
• Josh Harper
• Cole McDonald
• Sean Haggerty
• Matt Johnson
• UBMS Staff
Questions?