edited by
TIMCHAMPION
safety tips
Johnson C. Smith Univenily CharMe, NC 28216
Safety Is No Laughing Matter Patricia S. Hill and Thomas G. Greco Millersville University, P.O. Box 1002, Millersville. PA 17551 Each fall semester a new group of students, many of whom have little to no previous chemistry lahoratory experience, fill the general chemistry rosters a t our university. Durinp the first laboratory session i n all courses, substantial ti& is spent demonstrating and teaching proper techniaues for the safe handling of chemicals and equipment and for the operation of various safety devices suchas eye wash stations, showers, and fire extinguishers. Students also read and sign a n extensive safety checklist that i s discussed during the first lab session. In order to reinforce our commitment to developing stndents who practice "safe chemistry", we begin our fall chemistry seminar series with a presentation on safety in the lahoratory. Regular attendance a t chemistry seminars is encouraeed bv" awardine extra credit points in general. organic, and quantitative analysis courses for attending a certain proportion of seminars during the semester. Students obtain faculty signatures in oFder to verify attendance. In addition, all paid student lahoratory assistants are required to attend the safety seminar. Such a safety presentation might conjure up expectations of a boring rehash of seemingly endless lists of do's and don'ts for students to hear and remember. In order to raise our students' awareness of and interest i n safety, we have introduced what we believe to he a novel method of presentation. I t attempts to ensure that the students will remember most of the important do's and don'ts of safety. For the past four years, we have put on a safety skit i n conjunction with the showing of the ACS video Starting w i t h Safetv. Then we eneaee beginnine students in a contest to identify and list tKe-mos~safet~violations they observe during the skit. The contest winner (student with the most correct observations) receives a molecular model kit provided by our ACS Student Affiliates organization. Of course, the "actors" for the skit are two faculty members, one of whom is the department safety officer. They portray "typical general chemistry lab partners" who are making up a missed titration experiment lab. At the conclusion of the skit, contest sheets a r e collected and a group discussion of the observed safety infractions occurs between the audience and the actors. C o ~ i e of s the skit's s c r i ~with t all safety violations noted with numbers in parentheses and a corresponding table of safe lab practices are distributed also (See tahle). We present the skit's script with the hopes that vou will adapt it to suit the needs of vonr students and facul"ty and to enliven a n important topic. The skit requires a few simple props that should be readily available in the laboratory. It can be performed i n almost any sized room as long as there i s a bench or tahle to simulate a lahoratory workbench.
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Props t a b l e or demonstration bench test tubes with colored water in rack metal test tube holder
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1126
Journal of Chemical Education
Bunsen burner and striker buret on stand scrupulously cleaned reagent bottles (glass with ground glass stoppers) one labeled ACID but filled with water and one labeled BASE but filled with water two Erlenmeyer flasks (one having a broken neck) thermometer four scrupulously cleaned glass beakers (two containing edible NaC1-unlabeled-and two empty clean transfer pipet (25 mL) beaker filled with water but labeled ETHER 100-mL graduated cylinder on tray (containing several milliliters of dish detergent) 50 mL of freshly diluted 6%hydrogen peroxide in dark bottle (CAUTION:oxidizing agent) Potassium iodide (KI) scoopula various beakers and flaskswith colored water or lemonade trash can two pairs lab gaggles . lab notebooks
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Actors Woman dressed in good clothes, wearing sandals Purse with makeup and small mirror (lipstick or mascara) Bag of carrot or celery sticks in plastic bag ~ a ofgchips or pretzels Can of soda Safer" gc,gglri on r.rp of head hkr hnirhnnd hldn dressed in shuns,T-shm and baietmll cap, wearing sandals and carrying a backpack and a pack of cigarettes Wearing glasses butno safety goggles
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Scene A young woman wearinggood clothes (1)and sandals (2) is at a cluttered lab bench (3) with a purse and lunch sack (4). A young man, dressed in shorts (5) and wearing sandals (6),enters andgreets he,: They are lab partners and must make up an experiment they missed (7). She is wearing her safety goggles like a headband (8)on her head and worming (incorrectly, of course1 (9) a test tube full o f colored liouid ouer a tall. vellaw Bunsen burner flame (10).Nert to the Bunsen burner rs a reagent bottle labeled "ETHER (11).
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She: Gee, I thought you weren't coming, so I started the experiment. He: Sorry I'm late but the prof was long-winded. I really need a smoke (12).Can you give me a light? She lights his cigarette with the Bumen bumr(l3).He thenplaces the liehted ciearette next to the bottle labeled "ETHER (14). . . She: Oh, hey, I brought along some munchies to keep us -going- this afternoon. Want some? Here, have a carrot stick and some chips (15).
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She hands him a carrot stick, takes one herself and offers him some chips.
He: Thanks, I'm starved. He takes a carrot. Hey, you got any salt?
She: Yes, one of these i s sodium chloride. Humm She looks at two beakers containing white solid chemicals.
Lets see which one was it? They dip their f i ngers into the beakers and taste each one (16).
Oh yeah, that's it. She hands him a can of soda.
Here's a soda to share (17).
He: Well, I guess we'd better get started or we'll never get out of here. Do you know what experiment we are supposed to do today? (20) She: Yes, I think it's the one on titration. Did you bring the lab manual? I forgot mine. He pulls out a lab manual from his backpack and hands it to he,: She leafs through the book and finds the experiment.
Here i t is. Acid-base titrations. I t says you must first pipet 25 m L of hydrochloric acid into a n Erlenmeyer flask. Which one is that? (21) Hepicks up aflask with a broken neck (221, then he changes his mind andgets one that is not broken.
He: Here this is i t She: Okay. She reads more of the lab book.
Why don't you do t h a t while I fill this buret with a solution of sodium hydroxide. He obtains the acid by mouth pipetting (23) directly from the reagent bottle (24)labeled ACID. He lays the bottle top on the bench (25).She pours out some base and proceeds to fill the buret and soill BASE all over the bench (26).She wines it uo with her han& (27) and then pours the extra BASEback into the reagent bottle (28). Continuing to read directions from the lab manual
Now i t says to dilute the acid with about 30 mL of water and mix i t well. He measures out the water andpours it into the acid solution (29).
He: Give me something to stir i t with. She hands him the thernometq and he mires the acidand water with it (30).He then wipes the thermometer on his shirt (31).
She: Now we have to add the base gradually to the acid until we see the endpoint. She starts rapidly adding base from the buret (32) but no color change occurs. They continue to add a n entire buretfull to the flask.
He: Gee, this doesn't seem to be working. There must be something wrong with these chemicals. He opens the reagent bottles and takes a big sniff (33).
Humm. They seem to be ok. Are you sure you read all the directions? Frantically she leafs through the lab manual.
She: I think t h a t was everything. Oh, oh. Maybe we did forget something. What is a n indicator? He: Whining. Does t h a t mean we have to start over? She spies the hydrogen peroxide and KI on the bench.
She: Humm. Lets have some fun. I wonder what would happen if we mixed up these chemicals? (34)
She pours about 50 m L of 6% HzOz into a 100-mL graduated cylinder containing 2 4 - m L dish detergent.
He: Gee, I don't think you should do that. She: Oh, don't worry so much. They wouldn't leave anything dangerous out for students, would they? She adds a large scoopulo of KI to thegraduated cylinder They watch wide-eyed as a large column of foam rises and overflows the graduated cylinder
He: Oh, oh! I think we'd better get rid of the evidence (35) and come back another time. They pour everything down the drain (36) and leaue without much cleanup effort (37).
I t has been our experience t h a t combining the video and skit into one presentation i s both effective and entertaining. The video introduces fundamental safety concepts, and the skit allows for their immediate application. Students are challenged to be careful observers. Winners of our "spot the safety violations contest" have been able to observe and list all the different poor lab practices during t h e 10-15 min-lonp skit. and most students observe a t least 15-20 violati~ns.Most students leave the seminar with a more ~ o s i t i v eattitude toward safetv and their ability to apply it. The more experienced s t u d e k s still find the seminar to be informative and relish the chance to spot infractions by faculty. Many junior- and senior-level students have seen the skit three or four times and look forward to getting a laugh from the faculty members' "academy award performances". Overall, we have found this experience to be worthwhile. I t should leave a lasting impression on students and result i n the responsible practice of lab safety. Safe Laboratory Practices 1. Wear older clothes to lab. 2. Do not wear sandals when working in lab. 3. Keep lab work space uncluttered. 4. Do not bring lunches into lab. 5. Do not wear shorts when working in lab. 6. Do not wear sandals when working in lab. 7. Do not work alone in lab or after hours without permission. 8. Wear safety goggles at all times. 9. Paint tubes withliquids beingheatedawayhm others or self 10. Adiust burner flames orooerlv. , 11. Ilo nor p x c flnrn~n~ble. near open flames 12. Smukmg in lal) i r nor pcrmitrco 13. Krrp hn~rand loose rlothing - away from flames 14. No smoking in lab. 15. No eating in lab. 16. Never taste chemicals. 17. No drinks in lab. 18. Never use lab glassware as food or drink containers. 19. Do not apply makeup in lab. 20. Come to lab well prepared. 21. Familiarize yourself with laboratory equipment. 22. Place broken glassware in the proper waste container. 23. Never pipet liquids by mouth. 24. Do not pipet directly from a reagent bottle. 25. Do not nlace the tom of reaeent bottles on the lab bench. 26. Usecare and a funnel whm pouring liqu~dstoavo~dsp~lls. 27. Du nor s.lpt~up rhcmirals w i t h your bare hands. 28. Ne\.er return cxurcs rhcmirnls to rhr reagent bottle. 29. Always add acid to water. 30. Never use a thermometer as a stirring rod. 31. I)n not uipr chcm~rslsonto rlothmg. 3". Always r m d a n d fnlln\v dircctior>scarefully. 3 Usecawon when nutlngthr smell ofn chrmicnl: wave the odor toward your nose. 34. Never do unauthorized experiments. 35. Do not trv to hide mistakes. 36. Dispose of all waste in the proper location. 37. Clean up your laboratory bench area when finished
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Volume 72 Number 12 December 1995
1127
