Transcript Water Filtration Lab

Opening Assignment
What is the primary goal of water
purification?
 Rotifers and Paramecium in some pond water viewed through a
microscope
 Water found in ponds, lakes, rivers and streams usually has a
wide variety of organisms living in it. Some of these living
things are too small to see without the aid of a microscope.
 Untreated water may look clear and clean to us, but may still
contain microorganisms (bacteria, protozoa, algae, rotifers,
worms, insect larva and others) that are invisible to our naked
eye. Because some of these organisms can cause illness if
ingested, it is important to remove or kill them from water
before drinking it.
Listed here are just a few of the many
water-borne diseases with the type of
microorganism that causes it:
 Hepatitis (virus)
 Polio (virus)
 Cholera (bacteria)
 Typhoid (bacteria)
 Giardia (protozoan)
 Cryptosporidium (protozoan)
Cholera cases and deaths for
2000:
 THE GLOBAL IMPACT OF
CHOLERA
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 Cholera is caused by the bacterium
Vibrio cholera. People become
infected after eating food or drinking
water that has been contaminated by
the feces of infected persons.
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 Control of cholera is a major
problem in several Asian countries as
well as in Africa. In the year 2000,
some 140,000 cases resulting in
approximately 5000 deaths were
officially notified to World Health
Organization. Africa accounted for
87% of these cases.
Continent Cases Deaths
África 118,932
4,610
America(s)
3,101
40
Asia**
11,246
232
Europe
35
0
Oceania
3,757
26
What are some of the ways water is treated?
 Boiling water kills some germs but does not remove all of them or
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chemicals and dirt.
Chemical treatment (chlorine) kills bacteria and viruses. It is the most
common method to disinfect water.
Flocculation happens when a chemical is added that makes small particles
collect together to form larger clumps that are heavier than water.
Sedimentation happens when particles settle out of the water.
Filtration moves water through layers of trapping material (such as sand) or
passes water through a membrane that has pores to exclude contaminants
such as microorganisms, dirt and chemicals.
Water treatment plants remove or kill microorganisms before sending
water through a closed network of piping and into our homes, schools and
businesses. With the exception of boiling the water, they may use all of these
methods mentioned above to make our water safe to drink.
Some filters keep things from passing
completely through by trapping them.
See how the red dots (the
contaminants) are trapped inside the
filter above.
Membrane filters are a barrier for contaminants in water that
are too large to pass through, and some contaminants will
have a problem getting through because of their odd shape.
When you make macaroni, the macaroni is mixed in with
water. To separate them, you pour both the pasta and the
water into a sieve or colander. The water goes right through
the holes, but the macaroni stays on top.
 Your group has been given a mixture of “microcandyisms”, but you
have discovered that not all the candy microorganisms are safe.
You need to somehow produce a cup of PURE NERDS.
 Your group must design and build a filtration system that will:
 Separate out the big microorganisms (Gobstoppers and Smarties)
first.
 Remove the bacterial-looking Mike and Ikes and Skittles from the
mix next.
 Produce a batch of pure NERDS!
 You and your partner(s) must design a filter using the supplies on
your tables or on the “free resources” table to filter the smallest
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 Use the paper plates as filter holders. Cut out the
center of the plate.
 Design a set of filters using any of the available
materials.
 Use your imagination to arrange holes in the plates,
netting, string or paper strips to create the size and
shape of holes for each filter that will get the job done.
 Filter your “water” onto another plate.
1.
What two physical properties of the microcandyisms
did you need to take into account in order to create
your filter system?
2.
What do you think would have changed if the objects
got wet or stuck to other objects?
3.
Google the term “activated carbon” and explain how
it works to filter water.
https://www.youtube.com/watch?v=hWBNI4EfPQI
 Get a blank piece of paper out and title it “Water
Filtration Experiment”. You will work with your group
again to design a water filter.
 Our question: Does activated carbon help to purify
water?
 Hypothesis: (If, then, because)
 If we use . . . .
 Variables:
 Dependent:
 Independent:
 Constants:
Materials List: Make a complete list of all the materials
you will use in your experiment.
Procedure: You will come up with your own procedures
using the materials available. Don’t forget to give specific
details on how you build it and on the metric
measurements you used.
 Since these measurements will be primarily
qualitative, create a simple chart to collect your data.
 Example:
Test A w/o Activated
Carbon
Water clarity at start
Water clarity at 5 minutes
Water clarity at 10 minutes
Test B with Activated
Carbon
 Get in your lab group from yesterday and write a “high
school” level conclusion that explains the following.
 Was your hypothesis supported or not? Explain
 Were there any possible sources of error?
 How can this information be used to create further
experiments?
 How can this information help society?
 You will now complete the water use worksheet to
estimate how much water you use (waste) each day
and then compare your total to someone who lives in a
more underdeveloped country.
 https://www.youtube.com/watch?v=mxwWOx9R6I8