Friday, August 27

The focus of Friday's class period was chemical safety. We went over the Student Safety Contract in our Survival Packet and discussed a variety of safety-related issues.

Mr. H talked about the need for safety-consciousness when working around flames. One hazard involves working with volatile and flammable substances when there are flames at the same lab table. A volatile liquid is a liquid which vaporizes quite easily. A flammable substance is one which catches on fire when exposed to a flame. Mr. H did a demonstration to illustrate the need for caution. He had a flask of hexane - a volatile and flammable liquid. He shook the flask to more fully saturate the air in the flask with the vapors of the volatile liquid. He then pulled the stopper off the flask and tipped it slowly over a long metal incline. Being heavier than air, the vapors of hexane fell down  the ramp towards a lit tea-light at the bottom of the ramp. Upon reaching the tea-light, the vapors immediately caught on fire. The flames traveled up the ramp following the vapors towards the flask. Mr. H quickly pulled the flask of liquid hexane away to keep it from igniting. The demonstration underscored the importance of paying attention to what is happening when working around flames.

There are other hazards of working around flames. Most importantly long hair and loose clothing can catch on fire. Mr. H showed us the location of the fire blanket and the safety shower in the classroom. A fire extinguisher is also in the room; it is to be opertated only by Mr. H.

Mr H re-emphasized the importance of goggles with a demonstration.  He showed us a stryofoam mannequin which had been repeatedly squirted with acetone (see picture at left). He then took an acetone bottle and squirted the mannequin on the side of the neck. The acetone carved out a 2-inch wide channel in the mannequin upon contact (see picture at right).

Mr. H also discussed the use of the eye wash. The eye wash is used if you experience a chemical splash or burn in your eye. You should wash your eye for about 15 minutes if you encounter such an accident. Use your fingers to hold your eye open while washing thoroughly with water. If you have contacts in (which isn't a wise idea), first rinse a couple of minutes and then remove them.

Mr. H did a demonstration of how to smell a chemical substance. When smelling a chemical substance, you should NOT close a nostril and snort the vapors into the open nostril. This is a very bad idea and is almost certain to lead to a headache by the end of the period. The proper way of smelling a chemical substance involves wafting it towards your nose. Often times we will use a fume hood when working with abnormally noxious substances. The fume hood is in the back of the room.

We watched a safety video which described and explained a variety of hazards of working with chemicals and in a chemical lab. Precautions were discussed and clearly portrayed.

Finally, we were given some time to put our names on our goggles and place them in the Period 3 drawers. And we were given some time to read the Student Safety Contract.

The period ended with Mr. H giving us a handout and discussing the idea of our class blog. The class blog is a collective endeavor of the students in our class to chronicle our journey through chemistry. The blog will become our book, written by us and for us. If we do a good job, it will become a personalized version of our textbook. We will be able to use it as a study tool and a reference tool. Concepts will be explained, principles will be discussed and the mathematics will be demonstrated. As we prepare for our quizzes and tests, we can reference the blog as a study tool.

Each day, a different student will be assigned the task of being the scribe. The scribe is responsible for putting together the blog post for that day. The scribe must do all the writing and place the blog as a post in Blogger. Any variety of items can be included in the post. Examples include scans of completed packet pages, photos taken with our camera phone or camera, video from a Flip video recorder or camera phone or camera, YouTube videos watched in class, links to useful websites, references to textbook pages, etc. The main idea that each scribe must keep in mind is that it is their responsibility to completely and fully document that day of our journey through chemistry. When we all do our best, we will be able to produce a product that we can be proud of and will want to use.

Thursday, August 26

Thursday's class began with a discussion of the Honors Chemistry Survival Packet. We were allowed a chance to ask questions about anything we didn't understand as a result of reading it. The Survival Packet describes the course, the grading scheme, policies regarding late work and makeup work, expectations and a lot of information about the course notebook and lab reporting.

When it came time to discuss the process of lab reporting, Mr. H asked us to get our course notebooks out. He discussed the parts of a lab report and demonstrated how the information applies to the first lab - Lab MM1 - Observation vs. Inference. Mr. H said that the title and the Purpose can simply be copied from the Lab Description page into our lab notebook.  He emphasized that every lab centers around a Purpose;  the purpose is the question that we are attempting to answer as the result of our lab activity. Mr. H said that he doesn't give us a procedure (except for really complicated labs) because the procedure simply emerges from the purpose.

Mr. H then describes the Data section of a lab report. He emphasized that the Data section is the location where the evidence is placed. This included observations, measured data, labeled diagrams, graphs, charts, calcuations and other documentation. Mr. H said that we should not write elaborate sentences or lengthy paragraphs; we should write clear and understandable notes.

Finally, Mr. H described the Conclusion of a lab as being the answer to the question. Mr. H distinguished between Conclusions (usually 1-2 statements), Conclusion/Discussions (more of a lengthy paragraph) and a Discussion of Results (in which the connection between the evidence and the conclusion are logically discussed). Mr. H requested that we remove pp. 7-8 from our Survival Packet and tape it into the front of our Lab notebook.

After discussing the Lab Reporting Process (pp. 7-8), Mr. H then gave us an opportunity to complete our first lab report. While this was occurring, markers were distributed throughout the room so that we could place our names on our chemical eye goggles.

After the completion of the lab, Mr. H showed a short video on the topic of Put it to the Test.

 

Then he did a demonstration on observation and inference. After lighting a candle and watching it burn for a minute, he blew it out and ate it. (What was that all about?) I guess some things in chemistry class will just be pure entertainment. I'm alright with that.

Mr. H then began to address the topic of laboratory safety. He showed us the Safety Contract on the last page of our Survival Packet. He assigned us the task of reading the contract, signing it, having our parents sign it, and returning it. From the sounds of it, Mr. H takes chemical safety quite seriously.

The remainder of the period included a discussion of eye safety. Mr. H explained who our lab group was and assigned us lab tables. He gave us a chance to place our goggles in our lab drawers. He then did a chemical demonstration in which he put the white of an egg inside of a petri dish. He placed the dish on the ELMO projector so that we could see it. Mr. H explained that the biochemical composition of egg white was very similar to the composition of our eyes. He placed a few drops of concentrated hydrochloric acid in the dish. Wherever the acid contacted the egg white, a reaction occurred that cooked the egg. Mr. H explained that the same type of interaction occurs between our eyes and acid. He emphasized the need to wear goggles at all times when in the lab. The point was that the lab environment was unsafe. An individual student may not be doing anything with chemicals, but because he/she is in a dangerous environment they are at risk. Acids can be projected from another lab table or simply two other students at the same table towards your eyes. The point was clear: wear goggles at all times.

Then Mr. H told the story of Jimmy. Jimmy worked at a factory where Mr. H used to work. Mr. H was a chemical engineer and Jimmy was in charge of the tanks in a waste treatment area of the plant. One day Jimmy had difficulty with a pump on a barrel full of sulfuric acid. He could not get the pump to work. In an effort to fix the pump, Jimmy removed his goggles so that he could see more clearly. When he pried the lever off the top of the barrel, the contents were under pressure and squirted out at Jimmy's eyes. Jimmy, who was married and the father of two young children, was rushed to the hospital for treatment. he never returned to work and, as far as Mr. H knows, had not regained vision in either eye. The story of Jimmy underscores the importance of using proper eye protection at all times. 

The period ended and Mr. H said we would talk more about safety on Friday.

(from Nature Magazine)