chemistry

there are three different methods explain the physics and chemistry of the methods separately each in a different page (1 page each - single spaced) you - - Explain the physical principles behind how the method works. The spectrophotometer uses light, the meters use voltages, etc. Figure out how your method works and explain, in your own words, so that someone who is new to these methods would understand. 

- Explain the chemical principles behind how the method works. This may involve reactions If so, provide balanced chemical reactions in your explanation. Explain, in your own words, so that someone who is new to these methods would understand. 

(add figures if available)

1- method 1: The pH meter

 https://www.researchgate.net/publication/301702485_pH_Principles_and_Measurement 

2- method 2: Dissolved Oxygen 

 https://www.fondriest.com/environmental-measurements/measurements/measuring-water-quality/dissolved-oxygen-sensors-and-methods/ 

more explanation of how Colorimetry works (using colorimeter) 

 https://www.azom.com/article.aspx?ArticleID=13983 

3- method 3: Dissolved Silica

 (use information in pages 567-569) https://www.researchgate.net/publication/258376588_The_silicomolybdic_acid_spectrophotometric_method_and_its_application_to_silicatebiopolymer_interaction_studies/fulltext/55dbfd4008aeb38e8a8b9773/The-silicomolybdic-acid-spectrophotometric-method-and-its-application-to-silicate-biopolymer-interaction-studies.pdf 

(the principles of a spectrophotometer)  https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Kinetics/Reaction_Rates/Experimental_Determination_of_Kinetcs/Spectrophotometry