Science Smarts: Stained
By PATTY ROOKS on September 2, 2023.
I have a new university student, and recently I had a message asking what kind of laundry detergent he should purchase as the one he has just is not working well. Of course we all have favourites, but I thought perhaps I would try out a few in order to provide an informed decision. Let’s get started! *Remember to ask an adult before doing this experiment. Materials Water Three small squares of cotton material 4 clear jars with tight fitting lids Measuring spoons Measuring cups Three different kinds of detergent Three similar sized cotton squares dirty (soil, juice, grease) Scissors Masking tape Marker Spoon Timer Procedure 1. Label the four jars with the masking tape and marker. For instance, you will have “no detergent” on one jar; “Detergent A” on another; “Detergent B” etc. 2. Set aside for now. 3. Choose what you are going to soil the cotton square with. You want it to be the same substance you are testing. It is important to have this controlled in your experiment as different soaps may clean different substances better or worse. We want to test it on the same substance and have a fair test. 4. Make the cotton squares dirty with your stain of choice. Rub it in well for 30 seconds. Place one soiled cotton square in each one of the jars. 5. Repeat until you have four strings in each of the four jars. 6. Measure ½ cup (125 mL) of tap water and place it in the jar labelled “no detergent”. Repeat for the remaining three jars. 7. Measure one tablespoon (15 mL) of “Detergent A”. Pour this into the jar labeled “Detergent A”. Stir this around gently in the water for 30 seconds. 8. Repeat with the remaining two cotton squares and detergents. 9. Set aside for 10 minutes. 10. Remove the cotton squares from the water and rinse gently in clean tap water for one minute. 11. Observe. What is going on? You should have observed that detergent of some kind was better than no detergent at all. This is because the emulsifying effects of the detergent in the water help lift the dirt (or whatever you soiled the cotton squares with) from the cotton material. This should have also been seen by your observation skills as the water with the detergent in them was likely slightly discoloured. I cannot guarantee which detergent cleaned the best, but I bet many of you out there would love to learn this information – as would I – let me know how your experiment turned out! Perhaps this would be a great science fair project? Mark your calendars as the Praxis AGM will be on Friday, Sept. 22, 2023 at 6 p.m. We are always in need of volunteers and board members. To get involved in science outreach in southeastern Alberta, please contact Patty at Praxis. Patty Rooks, Senior Scientific Consultant PRAXIS, “Connecting Science To The Community”. Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. Address: #12 826 11 Street S. E., Medicine Hat, Alberta, T1A 1T7 Phone: 403-527-5365, email: praxis@praxismh.ca 32-31
