Which Filtration Material Leads to the Best Drinking Water?

[Lnicole]

Hello, my child has conducted the experiment “Which Filtration Material Leads to the Best Drinking Water?” on this site however no change was observed between the variables filtering out the ink (granulated activated charcoal and powdered activated charcoal). All were still very dark in color afterwards and didn’t appear to filter out the ink. Did we do bleep incorrectly or is our result correct? What is the result supposed to be?

Moderator note: Project url: https://www.sciencebuddies.org/science- ... king-water

[Snehaarun]

Hi!

Would it be possible for you to take a picture of the results of the project? It would be great if the picture could include all the cups (just like the pictures in the original instructions for the project).

Also, did you use the color scale that was provided in the instructions to analyze the data?

The intended result of the project was to demonstrate that powdered activated charcoal would filter the water better due to increased rates of adsorption with a higher surface area. Granular activated charcoal, although having the same volume, would have a smaller surface area, leading to lesser adsorption of the ink.

It’s important to make sure that you keep several things constant. This is outlined in each of the steps of the instructions, but here are a few that are important:
1) The amount of water
2) The amount of ink used (0, 15, and 30 for different trials)
3) The number of grams of powdered/granular carbon constant (3 grams each)
4) How much time you wait for the water/charcoal mixtures to settle (10 minutes). 5) Mixing, stirring, and pouring should be as consistent as possible
6) Make sure that all the water drains out of the filter for the all the cups for all the trials

If you did keep all those amounts constant, and you completed all three trials for all three variables (no carbon, activated powdered charcoal, and activated granular charcoal), here are some possible reasons the experiment could have not worked:
1) Not allowing enough time for adsorption to occur
2) pH levels or presence of other substances in the water affecting adsorption
3) The powdered charcoal may not be fine enough to have significant differences
4) Human error (due to accidentally having multiple variables and not keeping things constant)

I hope this clears some things up. I would really appreciate if you took a picture so I can try to help you a bit more, and let me know if there were some parts of the instructions you didn’t understand/accidentally forgot to follow when setting up the experiment.

[Lnicole]

Thank you for your response. We did follow the instructions to the best of our ability (e.g. same amount of water, stated amount of drops of ink, waited 10 minutes to filter) however maybe we needed to wait more time for it to filter completely? Here are the end results of the 3 trials after 10 minutes. Varying levels of the liquid filtered out after 10 minutes so maybe we include that difference?

[Lnicole]

Here are the rest of the photos

IMG_5496.jpeg (2.67 MiB) Viewed 6759 times

IMG_5498.jpeg (3.5 MiB) Viewed 6759 times

[Snehaarun]

Thank you for the pictures!

I would give it a little more time to filter out the water, but I do think that the results are a little different than what was expected due to uncontrolled variables that are difficult to pinpoint. For example, substances in the water and problems in the charcoal itself could be giving these unexpected results.

[amyCC]

Hi - Snehaarun has given you good information and suggestions for troubleshooting.

It sounds like you were careful with the directions, but can you just confirm….the filters were layered (four filters), correct?

Can you let me know if you used the kit that is listed with this project or if you procured the materials separately?

Amy
Science Buddies