Science Buddies: "Ask an Expert"

Hi, Thanks for making this very helpful website available for my 12-year-old's science fair! She is modeling her experiment using "How to Make the Boldest, Brightest Tie-Dye!" https://www.sciencebuddies.org/science- ... st-tie-dye

1) In step 2 of the procedure, could you clarify why it calls for three squares of each of the five white fabrics, when they all seem to be put in the same sealable bag with the same dye? (We are modifying the experiment by using three different colors and six types of fabrics, so we are looking to eliminate redundancy... analyzing the hue, saturation, and brightness of 18 squares rather than 54 squares is much more feasible.)

2) In step 9a of the procedure, we mix 2 tbsp. of soda ash and 4 cups of warm water, but in step 10, only 1/2 cup of the soda ash solution is added to the sealable bag. What happens to the 3 1/2-cup remainder of the soda ash solution? Are there in fact two more bags, for a total of three bags, one for each of the three squares? This would explain why three fabric squares of the same type were not redundant, since any errors in dyeing in one bag or "batch" could be documented, and you would still have two more "batches" of good data.

My daughter is looking forward to this experiment! Thanks again for your help on this!

Beth

Hi Beth,

This looks like a fun project! Answers to your questions below:

1) The procedure calls for 3 squares of each fabric type to collect more color data as the dye uptake may vary a bit from square to square. In the "Collecting & Analyzing Your Data" you'll see that bleep 2 averages the color picker values for the 3 squares. Because you are testing multiple colors and more types of fabric you could choose to use just 1 square for each fabric type to make this more manageable, but your results may be less accurate since you'll only be testing 1 square per color/fabric combination. Running an experiment multiple times (e.g. 3 squares) and comparing results is a way to test your hypothesis more thoroughly.

2) I don't see any use for the remaining 3 1/2-cup of soda ash solution in the procedure either. You could reduce this ratio (1 tbsp. soda ash + 2 cups warm water) to minimize waste. However, by testing other colors you will need more ash solution for the other color bags so you may end up using it anyway.

Good luck!

Audrey

Hi Beth - Thank you for posting your questions here for your daughter's project. I apologize for any confusion in the procedure.

The project does anticipate that you do three separate trials of each fabric type (in three separate bags). This process of doing multiple trials helps ensure the repeatability of results.

The project has been updated today -- so please make sure you reload it. Step 7 now instructs the student to use three separate bags.

The quantity of the ash solution has also been updated. You will add the solution to each bag, but the quantity being made has been reduced.

I hope your student enjoys the project and the dye testing she does!

Amy
Science Buddies

Thank you, Amy and Audrey! The experiment's procedure is clear to me now that I see the three bags (for repeatability of results) and updated soda ash solution quantity. Keep up the great work!
- Beth