Sunlight, Salt Water & Solar Desalination – the effect container color may have on seawater desalination rates

Table: 1
Experimentation location: Home
Regulated Research (Form 1c): No
Project continuation (Form 7): No

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Grainger Engineering Office of Marketing and Communications. “Color of Water Bottle.” Color of Water Bottle | Physics Van | UIUC, Grainger Engineering Office of Marketing and Communications, 22 Apr. 2011,


Parise, Tom. “Water Desalination.” Water Desalination, 16 Dec. 2012,,collected%2C%20leaving%20the%20salt%20behind 


Zewe  |  MIT News Office, Adam. “From Seawater to Drinking Water, with the Push of a Button.” MIT News | Massachusetts Institute of Technology, 28 Apr. 2022, 





Additional Project Information

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Research paper:
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Research Plan:


PROBLEM STATEMENT: As time goes on and the worldwide population increases, humanity will require more and more fresh water. The current freshwater supply is becoming increasingly inadequate, and we need ways to create more. (Parise)

DESCRIPTION: There is an abundance of seawater that we can utilize to create more freshwater by removing the salt. This process is called desalination. One method of desalination requires utilizing solar energy. I will test different solar desalination rates using different colored water containers to determine its impact on the generation rate of freshwater from seawater. (Parise)


Questions and Answers


1. What was the major objective of your project and what was your plan to achieve it? 

       a. Was that goal the result of any specific situation, experience, or problem you encountered?  

       b. Were you trying to solve a problem, answer a question, or test a hypothesis?


Test different solar desalination rates using different colored water containers to determine its impact on the generation rate of freshwater from seawater.


2. What were the major tasks you had to perform in order to complete your project?

       a. For teams, describe what each member worked on.


  1. Using scissors, carefully cut your construction paper to fit the body of the plastic containers.
  2. Cover one of the plastic containers with black construction paper, one with white construction paper, and leave one without construction paper. Do not cover the hole. Make sure to remove all labels from containers.
  3. Use putty to attach the bendy end of the straw to the hole in the plastic container.
  4. Attach a funnel to the bendable end of each straw on the inside of the plastic container. Ensure the funnel opening is facing up.
  5. Use putty to attach the open end of each straw to a plastic cup outside the container through the ¼” hole in the cup.
  6. Cover the container opening with plastic wrap. 
  7. Place the washer on the plastic wrap and above the funnel. Repeat for each container.
  8. Cut 6 sheets of aluminum foil to 4in. high by 12 in. long.
  9. Use clear packing tape to attach the short ends of the aluminum foil sheets to the wooden dowels. You will need 2 dowels for each sheet of aluminum foil.
  10. You should now have 2 aluminum foil reflectors for each container. Set them aside.
  11. Attach one foil reflector along each of the long sides of the containers with clear packing tape.
  12. Mix 4 teaspoons of table salt with 750 milliliters of room temperature freshwater (approximately 3.25 cups) until the salt dissolves. 
  13. Make 2 additional batches for the other containers.
  14. Fill the black colored plastic container with 3.25 cups of seawater. Repeat for the white and clear containers.
  15. Bring the desalination device outside when the sun is shining.
  16. Make sure there are no clouds or high winds.
  17. Leave the device outside for 8 hours to desalinate.
  18. After the 8 hours are over, record the results.
  19. Repeat for 4-5 days.




3. What is new or novel about your project?

       a. Is there some aspect of your project's objective, or how you achieved it that you haven't done before?

       b. Is your project's objective, or the way you implemented it, different from anything you have seen?

       c. If you believe your work to be unique in some way, what research have you done to confirm that it is?


I researched desalination methods and Information about light absorption. I didn't find any information about how light absorption affects desalination rates, so I tested that.


4. What was the most challenging part of completing your project?

      a. What problems did you encounter, and how did you overcome them?

      b. What did you learn from overcoming these problems?


There could have been many errors that may have impacted the productivity and working ability of this desalination experiment. 

One random error could have been that the experiment was performed in winter! I performed this experiment during the week of the winter solstice, when the sun is furthest from the Earth. When I conducted the experiment, the desalination device was further away from the sun than it would have been during any other time of the year. Exposure to more solar radiation would have accelerated the desalination process. 

Another random error could have been that the temperature was changing from day to day. The fluctuating temperatures could have affected my device’s ability to convert freshwater from the seawater.

One systematic error that could have changed the outcome of this experiment may have been the structure of the freshwater collection device! The funnel position kept changing. It was tilting more to the side rather than remaining upright, preventing it from collecting any freshwater. This could have been a result of the straw not being able to support the funnel. While I knew that the water was evaporating due to the droplets on the plastic wrap, none of the water made it to the freshwater cup.

A final systematic error was that there was no cover to the freshwater collection cup. It is possible that any collected freshwater quickly evaporated before I could measure it. 

5. If you were going to do this project again, are there any things you would you do differently the next time?


I would try my project in the summer when the desalination device would be exposed to more UV rays and heat from the sun.


6. Did working on this project give you any ideas for other projects? 


I would like to try my project again at a different time of year.


7. How did COVID-19 affect the completion of your project?