Reflection

After this long experimental process it is time to reflect.....

What would I change in my experiment if I could complete it again?

- I would conduct more background research to broaden my knowledge, relating to my           experimental hypothesis, before commencing the practical phases
- I would have been more organised in gathering all materials and items needed so my           experiment could be more accurate 
- I would repeat my experiment a further 2 times to ensure the experimental results are        
reliable 
- I would have taken more time when measuring different materials to improve the validity of   my experiment and may have considered filtering the liquids at home before the                     experimental lesson to save time

The outcomes for this experiment where overall successful.

I measured turbidity of the filtered and non-filtered liquids and then calculated and graphed the difference between the average turbidity’s of the filtered and non-filtered liquids. At the end of my experiment the average difference between the filtered and non-filtered dirty water was 671.2NTU, the black tea was 84NTU, the Coca-Cola was 56.5NTU and the soapy water was 131.1NTU. The turbidity of the dirty water will change the most drastically when it is filtered, followed by the soapy water, then the black tea and finally the cola-cola. There is not evident trend from my results although, it can be assumed that the turbidity’s of the liquids that had larger particles in them (such as the dirty water and the soapy water- dirty particles and bubbles made from the detergent) changed more drastically when filtered than the liquids (Coca-Cola and black tea) in which had dissolved particles in them. 

Conclusion: In conclusion, the effective water filter successfully filtered different liquids, causing the turbidity of the liquid to change. The turbidity of the dirty water changed the most drastically when it was filtered followed by the soapy water, then the black tea and finally the cola-cola, therefor proving my hypothesis to be correct. 

Overall I would say this was a successful project and I am very pleased with the result. Thank you for being a part of my Science Experiment for 2016. 

Discussion

In reference to that shown in the results the outcome of my experiment was relatively what i had predicted in my hypothesis and expected. I measured turbidity of the filtered and non-filtered liquids and then calculated and graphed the difference between the average turbidity’s of the filtered and non-filtered liquids. At the end of my experiment the average difference between the filtered and non-filtered dirty water was 671.2NTU, the black tea was 84NTU, the Coca-Cola was 56.5NTU and the soapy water was 131.1NTU. The turbidity of the dirty water will change the most drastically when it is filtered, followed by the soapy water, then the black tea and finally the cola-cola. There is not evident trend from my results although, it can be assumed that the turbidity’s of the liquids that had larger particles in them (such as the dirty water and the soapy water- dirty particles and bubbles made from the detergent- as shown in the picture below) changed more drastically when filtered than the liquids (Coca-Cola and black tea) in which had dissolved particles in them. 

Reliability: I only completed my experiment twice which may have led to unreliable results. This experiment should be repeated several time to ensure the same result is obtained using the same method. Further testing could have been carried out to ensure reliable results. I carried out two experimental tests for my experiment, however for extremely reliable results I could have done a further test, in which would have created more accurate outcome/results of my experiment. 

Accuracy: In order to effectively improve the accuracy of this experiment, the equipment used for testing could have been more accurate. I have not used a turbidity meter before and thereby was not familiar with this sort of technology. Although I was shown a demonstration on how to use the turbidity meter I could have done more research and become more familiar on how to use the turbidity meter, thereby using it to its full potential. When I washed the sand and the gravel I used my hands and cleaned as much dirt and other unwanted particles out of these materials, although some particles of dirt may still be presents in these items. To improve the accuracy of the cleaning of these materials I could have repeated the cleaning process numerous times, and after each time letting the water drain out of the materials. This will improve the purity of the sand and the gravel, in which if they still have unwanted dirt in them, could affect the results/outcome of my experiment as these dirt particles could drain into the filtering liquids, affecting the turbidity. 

Validity: To effectively improve the validity of this experiment, all variables needed to be controlled. The measurements of the components of my natural water filter (sand and gravel) should be controlled to prove fair results, although whilst measuring these liquids I may have been rushing and estimated different amount of liquids. This could affect the filtering capability of my natural water filter, causing my results to be invalid. In order to overcome this issue I need to take more time when measuring the amount of materials I need for my experiment, thereby proving more valid results.

Was my Hypothesis Correct?

My hypothesis is as followed: 'The turbidity of the dirty water will change the most drastically when it is filtered' 

The outcome of my experiment was the same as my hypothesis as the turbidity of the dirty water changed most drastically than the other liquid when it was filtered. In the dirty water I added a small bowl of garden dirt to 1 cup of water and 1/4 teaspoon of vegetable oil. The turbidity of a liquid is the cloudiness or haziness of a fluid caused by large numbers of particles that are generally invisible to the naked eye. The other liquids I tested including black tea, soapy water and Coca-Cola did not contain as large particles as the dirty water (as the soil does not dissolve in water) therefore when these liquids where filtered they did not change their turbidity’s as drastically as the dirty water did. This is the reason why the turbidity of the dirty water (671.2NTU) changed more drastically than the Coca-Cola (56.5NTU), black tea (84NTU) and the soapy water (131.1NTU)

Below I have attached a video, to help explain how I have conducted my experiment, hopefully making it easier to understand: 

Results + Photos

I have completed my experiment and recorded all results in a table. I measured turbidity of the filtered and non-filtered liquids and then calculated and graphed the difference between the average turbidity’s of the filtered and non-filtered liquids. At the end of my experiment the average difference between the filtered and non-filtered dirty water was 671.2NTU, the black tea was 84 NTU, the Coca-Cola was 56.5NTU and the soapy water was 131.1NTU. The turbidity of the dirty water will change the most drastically when it is filtered, followed by the soapy water, then the black tea and finally the cola-cola. 
My results table is as follows: 







My results graph is as follows:
















Comparison photos of the non-filtered and filtered liquids: 

BLACK TEA:

     - Smell of tea changed – not as strong

-    - Colour of filtered tea became lighter

-    - Bubbles formed at the top of the liquid

-    - Tea became cold

-    - Took roughly 20+ minutes to filter fully

DIRTY WATER:

-     - Colour of filtered water became lighter

     - No dirt particles present to the human eye in filtered liquid

-    - Took roughly 20+ minutes to filter fully

         
COCA-COLA:

-    - The colour of the liquid changed – became lighter

-     - More bubbles formed

-     - Took roughly 10-15 minutes to filter

-     -  Smell changed- reduced 

          
SOAPY WATER:

-     - Took roughly 15- 20 minutes to filter fully

-     - Bubbles rose to the top of the liquid

-     - Bubbles still visible in liquid

-     - Colour changed (due to other liquid residues)

Background Research -Turbidity (Article)

Today I decided to complete some more research about Turbidity and the issues surrounding this topic. Using http://water.usgs.gov/osw/techniques/TSS/ZieglerT.pdf I have written a brief summary of my understanding of the article (see below):

Turbidity Definition: 
Turbidity can be defined as a decrease in the transparency of a solution due to the presence of suspended and some dissolved substances, which causes incident light to be scattered, reflected, and contracted rather than transmitted in straight lines; the higher the intensity of the scattered or attenuated light, the higher the value of turbidity. 
Turbidity can be expressed in nephelometric turbidity units (NTU). Depending on the method used, the turbidity units as NTU can be defined as the 'intensity of light at a specified wavelength scattered or attenuated by suspended particles or absorbed at a method-specified angle, usually 90 degrees'. 

Issue Relating to Turbidity Measurement: 
Different Turbidity methods, standards, reporting of units, and instruments are not identical meaning that because turbidity is an apparent optical property of water, it is likely that dilution of samples would not result in a physically reproducible measurement. 

Light wavelengths are different, and color can affect the measurements. Different instruments may use forward or backscatter detection devices and multiple incident light sources and detection devices at different orientations that can compensate for the effects of color and grain size. Therefore, measurements of the same water by different methods and different instruments are not likely to produce similar values.

The color of water can cause a negative bias in measurements by constricting the light in colored samples. The color of the darkened sediment particles has been shown to substantially affect measurements with optical backscatter meters, and it is expected that nephelometers would give a similar negative bias in measurements depending on the minerals in the sediment . 
All turbidity meters can be affected by the grain size and orientation of the sediment in a sample liquid.

Variables in my Experiment

Variables: A variable is any factor that can be controlled, changed, or measured in an experiment. These are the variables in which I needed to change, measure and control whilst completing my experiment: 

Independent variable: The type of liquid (I used four different liquids to experiment with including Coca-cola, Dirty water, Soapy Water and Black Tea)

Dependent variable: The turbidity of the liquids before and after they are filtered (I measure the each liquid before and after it was filtered using a Turbidity Sensor) 

Controlled variables: Same amount of each liquid being filtered, same type of filter (with same amount and type of materials), same amount of liquid used when testing the turbidity, same type of equipment used to measure the turbidity

Variable that needs to be controlled	How this variable will be controlled
Same amount of each liquid being filtered	Use a measuring cup to measure exactly 1 cup of the liquid that you will be filtering.
Same type of filter (with same amount and type of materials) (this includes the amount of filter paper used)	Use the same filter each time you are filtering the different liquids. Make sure you use a measuring cup to measure exactly 1 cup of each material that is made up of the filter.
Same amount of liquid used when testing the turbidity	Only fill the glass bottles up to the line when testing the turbidity of each liquid using a turbidity meter.
Same type of equipment used to measure the turbidity	Only use a turbidity sensor to measure the turbidity of each liquid.

Conducting my experiment in class

During last thursday and friday's science lesson we were given an opportunity to conduct our SRP's. I had to make a few changes to the materials I used. I did not end up using the 'activated charcoal' as I was not able to buy the charcoal in time for my experiment. I got some charcoal from my house fire but realised that this was not the same as activated charcoal and did not contain the same properties as activated charcoal does in relation to filtering different liquids. Below are some photo's of my experiment:


The setup of my experiment:

Liquids I used for my experiment:

I used a data logger with a turbidity sensor attached to measure the turbidity of different liquids (Picture of this measurement tool below): 

Below is a video of liquid being filtered:

I have also attached a comparison picture of the liquids before and after they have been filtered. I will post about my results in a later post. 
Liquids before they are filtered:

Liquids after they have been filtered: