Your lab partner spilled the bottle of alcohol all over the floor again, only this time a nearby Bunsen burner set it ablaze and you’re standing right in the middle of it all. Good thing you weren’t wearing your favorite outfit today. Just what are you wearing though? Will it help protect you? Will it burn easily? Is it something that melts and fuses to your skin? Does it produce toxic fumes? Who knows, maybe it’s even something that evaporates, leaving you naked in front of the class. Obviously, you need to know these things.
OVERVIEW
You will evaluate how different cloths perform when exposed to flames. You will select several different materials, choose one or more flame sources, and attempt to ignite the cloth. You will observe and record all findings, with an eye towards determining which cloths offer the most protection from fire.
DESIGN
While the experiment itself is easy to perform, there are a number of things you’ll have to consider beforehand. The first is which cloths you want to test. There are many to choose from, both natural and synthetic, and of varying thicknesses, colors, textures, etc. It would be good to get a wide selection, making sure to include both natural (cotton, wool, hemp…) and synthetic (nylon, rayon, polyester…) cloths. You may want to get different types of the same cloth to see how thickness, color, or other variables affect their fire protection ability.
You’ll also have to choose your flame source. Different sources give different temperature flames, and it will be important to know what temperature you are dealing with. Options include a candle, paper, wood, Bunsen burner, alcohol burner, or even gasoline. Make sure you have a controlled source, so the fire won’t get out of control. It is better to have two or more flames of different temperature, so you can see if the cloth offers more protection in a lower temperature flame. (You’ll have to look up the temperatures at which each material burns, often called the ignition temperature.)
Location matters too. Where is all this burning to take place? Ideally, you will use a fume hood. That will prevent you from breathing any toxic fumes or smoke that may form. If a fume hood is not an option, then work outside, or somewhere well-ventilated. If there is wind, stay upwind from the fire while working.
Finally, there is delivery to consider. How will you introduce the flame to the cloth? Will you just hold the cloth in the flame with tongs? Will you wrap the cloth around a dummy that represents the wearer? Perhaps you’ll choose the blind date method – “Mr Flame, this is Miss Cloth, Miss Cloth, I’d like you to meet my good friend Mr. Flame. Why don’t you two get to know one another and see if there are any sparks?” Once you’ve achieved a flame, you may want to be able to extinguish the flame, so have a tub of water handy to plunge the cloth into.
SAFETY
Since you’ll be working with fire, make sure you’re adequately protected. Of course you should wear your goggles, lest you splash hot fuel in your eyes. Avoid wearing loose hair, jewelry or clothing that could droop into the flame. As mentioned earlier, make sure you have proper ventilation. Have a second person on hand that can call for help if something does happen to you. A flame-retardant lab coat is a good idea as well. Check first – not all lab coats are meant to be used with fire. Expect everything to be hot, even when it looks cool. Use tongs, hot mitts, or some heat protection when handling anything that has been in, or even near, a flame. Make sure there is at fire extinguisher handy.
EXPERIMENT
Create a data table that lists your different cloth samples on the left, the type of flame on the top, and plenty of open space at the intersection of the two for your predictions and observations. Predict what will happen to each cloth sample before applying fire. Then execute the experiment, following the proc edure you’ve designed. Carefully observe what happens to the cloth. Note how long it takes to catch fire (if it does), whether it melts, gives off smoke, and any other details.
REPORT
Use all the data to evaluate all your observations. Rank the different cloths for how much protection they offer. Which is best? Which is worst? What recommendations can you offer to lab students dressing for lab day? Compare your findings against what lab coats are actually made from. It might add a personal feel for classmates if you survey them all on a given lab day to see what cloth they are wearing too.
Good luck, be safe, and if you do happen to find an evaporating cloth, make sure to tell this author.
