Principle:
Turbidity is the cloudiness of the liquid due to the presence of suspended
particles that are invisible to naked eyes. Turbidity can be measured using
turbidometer. Turbidometer (or called nephelometer) is an instrument which is used
to determine the turbidity of liquid. It depends on measuring the amount of light
reflected by the suspended particles. The amount of light reflected is directly
proportion to the amount of partials present in a liquid (turbidity).
Turbidity can also be measured by measuring the transparency of the liquid
using spectrophotometer (transmittance mode). Clear liquid (not turbid) has higher
transparency (near 100%), turbidity decrease this transparency.
Meter (measures the amount of reflected lights)
Transmittance light
Light source
Transmittance light
Suspended particles
This figure is referred to turbidometry.
Applications:

Determine the water quality.

Test the dissolved O2 in water.

Formation of Ab-Ag complex.
Materials:

Different concentration of calcium chloride (0.1 g%)

Dionized water

Distilled water

Tab water

Drinking water
Instruments:

Turbidometer

Spectrophotometer
Procedure:
1- Prepare the following samples to measure turbidity by two instruments:
turbidometer and spectrophotometer.
(Samples: calcium chloride, dionized water, distilled water, drinking water and tap
water)
2- For each sample add equal amount (1 ml) of sample and Sulcowich reagents, mix
well, then wait for 3 minute. (Note: If you are use cell in the spectrophotometer,
add equal amount (5 ml) of sample and Sulcowich reagents).
3- Read turbidity in NTUs (Nephelometric Turbidity Units) by turbidometer.
4- Read transmittance by spectrophotometer at 340-350 nm.
See the below steps to learn how to use the turbidometer.
Sample holder
Zero control
Change the range of
reading from 20 to 200
Sample tube
Blank tube
(deionized H2O )
First way using turbidometer:
1. Collect the sample in the sample bottle.
2. Use blank (deionized H2O) to calibrate the turbidometer.
3. Put the sample in the holder.
4. A sample is collected in bottle of sample.
References:




http://water.me.vccs.edu/concepts/turbidity.html
http://en.wikipedia.org/wiki/Turbidometry
http://en.wikipedia.org/wiki/Turbidity
http://turbiditymeteroutlets.co.cc/reviewsVWR_TURBIDITY_METER_DIG_800___VWR_Model_800_Turbidity_Meter___Mod
el_66120_200___Each-B001UHRN7A.html
Result Sheet
You name: ---------------
Substance name
Write your observations here.
Turbidity
Transmittance