The age-old question “What should I wear today?” takes on new meaning when the chemistry teacher announces that tomorrow’s lab will use concentrated acids. Indeed, what should the student wear? Looking great may be important, sure, but it does little good if it turns out that those highly fashionable garments melt away when exposed to acid vapors. Some cloths are better suited to the chemistry lab than others, so it’s a good idea to find out which they are. This article will guide you in developing your own unique experiment.
Step One: Decide what properties to test.
You’ll have to decide what aspects of the cloths to study before you can design the experiment.
Do you want to find out which (and how fast) cloths dissolve in acid?
Do you want to know which cloths absorb acid?
React with acid?
Offer splash resistance?
Allow acid to wash off easily?
Are you interested in small splashes or large spills of acid?
Step Two: Design the basic experiment.
For each property you want to investigate, you’ll need a controlled experiment. The only variables in a particular experiment should be the cloth and the acid. Keep in mind your choices from Step One as you work through the design phase.
Decide on an appropriate method for testing the desired property. You’ll need to determine a method of delivery.
Do you want to dunk the cloth into the acid?
Spray the cloth with a small amount of acid?
Hang the cloth over acid and expose it to vapors?
Rinse the cloth with water after a certain amount of time?
How will you measure the effect of the acid on the cloth?
Will you observe at certain time points?
How long will you let the cloth sit?
What will you observe?
Are you looking for holes?
Whether acid can soak through?
How much acid the cloth can soak up?
Will you need a pH indicator to see whether acid is present?
What protective equipment will you need? Presumably you’re going to want the basics - a lab coat, goggles, and gloves, but you should also consider whether you’re going to need a fume hood for acid vapors, and what kind of spill kit you should have on hand for clean-up in case the inevitable happens.
What acids will you test? You have numerous possibilities: nitric, sulfuric, acetic, hydrochloric, formic, and many others. What about concentration? Are you going to test only concentrated acids, only dilute acids, or both?
What cloths will you test? Not only can you consider different fibers (cotton, wool, nylon, polyester, rayon, hemp, linen, etc.) but you can also look at different weaves. Is denim (which is cotton) better or worse than, say, a lightweight cotton blouse?
Step Three: Make your predictions.
Science fairs always want a hypothesis, so go ahead and give them one. Take your best guess at which cloths will do the best (or the worst), and which acids will be the hardest to protect against. If you want, this is a good opportunity to do some background research. See what you can learn about different acids and cloths from existing articles. Then you can make a more educated guess about what to expect. It’ll also be more interesting if you have the chance to disprove what someone has written before.
Step Four: Gather your materials.
Now that you have a plan, round up all the pieces that you need. Remember to include plenty of paper on which to record all your procedures and observations. It’s a wise idea to set up nice, organized charts to record all your data in beforehand. That way you’ll be able to make sense of it easily when you try to write your report later on.
Step Five: Do the experiment!
All that preparation pays off - now. With everything planned out and ready to go, now you get to focus on the fun part. Just remember to record every step along the way, especially if you depart from your original plan. Writing by hand isn’t the only way to record things either. Pictures and/or video also work.
Don’t forget to clean up afterwards. Leaving acids lying around is just asking for trouble.
Step Six: Put it all together.
Now that you have all your data, you have to interpret it. Which materials held up the best (or worst) under what conditions? Did your predictions come true? How will you showcase your results? Is a graph appropriate? A Table? Pictures? Actual pieces of cloth? The final format of the report and presentation is ultimately up to you (and your teacher), so just make sure that everything is included, including references to any research sources you may have used in learning about cloths and acids. (You may even want to list this article.)
Step Seven: Share your results.
Yes, give your presentation to the science fair judges by all means, but pass on the information to your classmates, friends, family, and whoever. Now that you’re the expert on acid safety, you can take a part in making sure everyone else knows what the best things to wear are for the next lab day. The author wouldn’t mind hearing how your experiment turned out, either.