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Science fair presentation

science fair!!!

Amelia Wootton

on 10 April 2013

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Transcript of Science fair presentation

Experiment: Chlorine vs. Salt Problem: How does the type of water swum in effect how quickly a bathing suit wears out?
IV: type of water
DV: how quickly a bathing suit breaks down
Control: freshwater Hypothesis: I think that the bathing suit will break down fastest in chlorinated water because...
chlorine is a stronger chemical than salt
similar to bleach which breaks down fabric Background Information:
purpose of chlorine:
to kill microorganisms (harmful germs)
to maintain pH level of water so that it is safe and comfortable for swimmers
disinfecting process: chlorine breaks down into HOCI (hypochlorous acid) and OCI (hypochlorite ion), attacks bacteria (destroying harmful enzymes), break down into single cell atoms and become harmless
OCI causes fabrics to fade faster
used ocean water because salt in pool serves same purpose as chlorine, just a different process
33-37 grams of salt per liter of water in the ocean
large range because of...
less salt near equator from more rain
less salt near the poles from melting ice Bibliography for Background Information:
"How does chlorine work to clean swimming pools?" How Stuff Works. N.p., 6 June 2001. Web. 3 Mar. 2013. <http://science.howstuffworks.com/innovation/ science-questions/question652.htm>. "Salt vs. Chlorine." Wright's Pool Service Inc. N.p., 2011. Web. 3 Mar. 2013. <http://wrightspoolservice.net/salt-vs-chlorine/>. "Sea Water." National Weather Service. N.p., 5 Jan. 2010. Web. 5 Mar. 2013. <http://www.srh.noaa.gov/jetstream/ocean/seawater.htm>. "Swimsuit Chemistry." Ohio State University: My Plan for Health. N.p., 2006. Web. 3 Mar. 2013. <http://researchnews.osu.edu/pamfrostgorder/2009/05/04/ swimsuit-chemistry/>. "Why is the Ocean Salty?" The USGS Water Science School. N.p., 10 Jan. 2013. Web. 3 Mar. 2013. "Your Disinfection Team: Chlorine and pH." Centers for Disease Control and Prevention. N.p., 12 Apr. 2010. Web. 3 Mar. 2013. <http://www.cdc.gov/healthywater/swimming/pools/ disinfection-team-chlorine-ph.html>. Materials:
-At least 18 liters of fresh water
-Chlorine testing strips
-Between 2 and 3 bathing suits
-3 large buckets
-Safety pins
-200 grams of salt
-2 large spoons
-Large plastic bag
-Chlorine tablets or bleach
-Plastic wrap Procedure:
1.Using the ruler, trace 7.62 by 7.62 cm squares on the bathing suits so that there are 16 squares. Label them by type of water and trial number (do 5 trials per water type). Use one as a sample to look at under a microscope.
2.Cut out the squares using the scissors and pin the two layers of the bathing suit together with a safety pin.
3.Fill one of the three large buckets with 6 liters of fresh water and label it “fresh water”
4.Fill one of the other buckets with 6 liters of fresh water.
5.Then, add 200 grams of salt to the same bucket and label it “salt water”
6.With the spoon, mix the water until all of the salt dissolves.
7.Fill the last empty bucket with 6 liters of fresh water.
8. Chlorinate the water
Water chlorination process
:If chlorine tablets are being used:
a.Break a tablet into small pieces in the large bag using a hammer and put a gram of the chlorine powder into the water
b.Using the other large spoon, mix the water until the chlorine dissolves
c.Test the water with the chlorine testing strips
d.The chlorine level should be between 7 and 10
e.If the level is too high, add more water until chlorine level is correct. Then, take out water until there is 6 liters left. If the chlorine level is too low, add more chlorine until it reaches and adequate level.
If bleach is being used: (do not use both bleach and tablets)
a.Use the eyedropper to insert 3 drops of chlorine into the 6 liters of water
b.Test the water using the chlorine testing strips. The chlorine level should be between 7 and 10
c.If the level is too high, add more water until chlorine level is correct. Then, take out water until there is 6 liters left. If the chlorine level is too low, add 1 drop of bleach at a time until it reaches and adequate level.
9.Place the five fabric squares marked chlorine into the bucket of chlorinated water. Put the five fabric squares labeled salt into the bucket of salt water and put the fabric pieces labeled fresh into the bucket of fresh water.
10.Cover all three of the buckets with plastic wrap
11.Every two days, measure the length and width of each bathing suit square.
12. Also every two days, using the chlorine testing strips to make sure the chlorine level is between 7 and 10. If not add more chlorine (See step 8)
13.In addition, every two days, make sure no water has evaporated even though the buckets are covered. If any water has evaporated, add more.
14.Cover the buckets each time.
15.Leave the bathing suits in the water for two weeks. Once the two weeks is up, remove the squares from the buckets. After squares have dried overnight, observe them under a microscope. how to cut the bathing suit fill buckets adding salt to the water fresh water water chlorination finish set up what comes after Results: Data Tables and Graphs
Fresh water: fabric maintained same size of 7.62cm x7.62cm Salt water: fabric maintained same size of 7.62cm x7.62cm Chlorinated water: Trial 1 fabric expanded on day 10 about .5 of a cm to be 8cm x8cm Pictures: fabric before experimentation fabric after being in chlorinated water for two weeks *the other fabric pieces showed no color change Conclusion:
-hypothesis: I thought that the chlorine would impact the fabric (and make it expand)
the most because chlorine is bleach, and it breaks down fabric
-hypothesis is valid
-saltwater and control (freshwater) had no change in fabric size or color
-both stayed at 7.62cm x7.62cm
-little change in fabric in chlorinated water in size since only 1 trial expanded
-expanded from 7.62cm x7.62cm to 8cm x8cm
-can see this in graph
-trial 1 might be an outlier since none of the other trials expanded at all
-not necessarily accurate because drag while swimming causes expansion,
but I wasn't able to simulate that effect
-the flaw could be changed by using filters from fish tanks (one for each trial) and
securing fabric to the side of the tank under the filter
-another error was in chlorination
-hard to keep the water at a constant chlorine level even with testing often
-when fabric was placed in water, it curled up and sunk, so some areas were not effected (see pictures)
-to improve this, a plastic frame could keep it from curling up
-add to procedure:
-make sure that the buckets of water are kept at a consistent temperature
-keep the buckets in a dark area
-this will make sure a constant, yet minimal amount of water evaporates
-do experiment for as long as time permits because results will only improve
-five trials to increase validity and decrease the chance of getting an outlier
-important to have a control because it gives baseline results for comparison
-I used a microscope to look at fabric in chlorinated water and freshwater and compared them
-chlorine fibers were farther apart
-fabric in chlorinated water also turned whitish-pink (affect of bleach)
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