November 24, 2017

I choose to teach!

apple web size copyOur culture is the exponentially growing collection of knowledge and invention that we pass from one generation to the next.  Science and mathematics are especially rich components of our culture with millenia of contributions from many cultures and all regions of the globe.  Unlike other forms of inheritance which must be subdivided and are often distributed with inequity, this inheritance is the birthright of every person, and every person may consume as large a share as he or she would wish. Our world is one of science, mathematics and technology; literacy in these areas is essential for any individual who is to be engaged with and empowered in our world.  The curriculum is a subset of this inheritance which is distilled down and shared with students in the environment we call school.

The America that we know today was built by those who left their homelands because they were not first-born sons  and therefore had very limited birthrights.  Others came from situations where even first-born sons had few if any prospects.  With an education in America a person has prospects to not only survive but to thrive and to provide for children.  But if we measure the value of an education solely in terms of economic benefit, then we ignore the greater part of its value.Owl Box

In times past you might have been a  carpenter because  your father was a carpenter whether or not you were well suited for that occupation.  You might have been a mother and a housekeeper because it was expected,  but even learning to read was not a possibility.  Perhaps you would have been a field hand because that was the only option available.  Carpentry, parenthood  and farm work  are all important roles, and they bring joy to those who choose them.  However, with education you may choose to be a nurse, or a doctor or a software engineer because  the work suits you well.  And along the way you may sculpt your own identity;  you need not accept the identity that others force upon you.

Students do not always appreciate the awesome value of this cultural inheritance, so  a primary function of the teacher is to help the student understand the meaning of the curriculum with respect to the life of the student.  Once the student is engaged the teacher serves as  a guide.  Success is  achieved when the student is  able to function as the most important person in his or her own education.  A successful education system produces graduates who are life-long learners that are able to learn and grow with or without formal schooling.   I teach as a matter of social justice. I teach to empower students. I teach so that students may understand their world, be part of it, contribute to it and reap its rewards.  I teach because the rewards of working with students greatly outweigh the economic remuneration that comes with teaching.

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Emergency Chemical Spill Center

Emergency Chemical Spill CenterShown is an image of the Emergency Chemical Spill Center that I created for a high-school chemistry lab.  I consulted with recommendations from Flinn Scientific.  See my post on Laboratory Safety with Flinn Scientific.  You can certainly purchase ready-made kits, and while they look rather pretty, they are not generally the best use of the laboratory budget.  I decided to use a heavy-duty cart placed in a central location.  For small spills there are small containers which may be retrieved and carried to the problem, but for larger spills the cart may be moved to the problem area.  The large (and therefore heavy) buckets each contain a scoop and are closed with plastic wrap that may easily be removed.

Baking Soda:  Baking soda,  also known as sodium bicarbonate or sodium  hydrogen carbonate, is the most commonly used item on the cart.  You can purchase individual boxes at the grocery store, and larger boxes may be obtained  economically from club stores.  It is very mild, and it can be used to neutralize both acids and bases.  For small bench-top acid spills students will liberally sprinkle the baking soda on the spill until the bubbling stops, and then the mess may be cleaned up with water and paper towels.

Baking soda is also a good option for small fires that could be extinguished with an ordinary ABC fire extinguisher.  Not only will the powder starve the fire of oxygen, but upon heating baking soda decomposes generating copious amounts of carbon dioxide further blanketing the fire from oxygen.

Carol didn't use safety gogglesSoda Ash:  I purchased a large pail of  soda ash from the local pool-supply store.  It is more potent than baking soda, but it is still easy to use.  It is an excellent choice for larger acid spills.

Dry Sand:  Dry sand is your option for fires which cannot be extinguished with water, carbon dioxide or an ABC fire extinguisher.  This includes fires involving Group I and Group II metals such as sodium and magnesium. Make certain the sand is actually dry and is kept dry!  An excellent choice is to bury the fire with an excess of sand.  A good follow-up would be to cover the whole thing with a fire blanket just in case there is an explosion from released hydrogen gas.

Sand is also excellent for containment of liquid spills.  Try to create a barrier around a puddle to prevent further spreading.  The grit may also provide traction and prevent slips and bodily injury due to slimy floor tiles that dissolve with an acid spill or a solvent spill.

Kitty Litter:  Kitty litter is cheap, and it is excellent for absorbing liquids.  It may be swept up and placed in a container, and neutralization may take place in that container.  For example, it’s a challenge to neutralize a strong base when it is spilled all over the floor.

safety signsInstructions:  Directions for using the cart and its contents are attached directly to the cart and placed on the wall above the cart.  Instructions, and when appropriate an MSDS, are attached directly to each bucket on the cart.  Students are routinely questioned about safety procedures, and every laboratory exercise has a portion of the grade assigned to laboratory safety.

Since taking this picture I have added a broom and a dustpan as well as safety gloves to the cart.  Naturally the lab also has fire extinguishers, fire blankets, an emergency shower, an eye-wash station, appropriate personal protective equipment, etc.  You can see a Fox E Flinn safety poster to the right of the picture; safety posters are all around the lab and the classroom.

Laboratory Safety with Flinn Scientific

It doesn’t matter how much time you have spent in a chemistry lab, when you are the one who is responsible for the lab and the students who use it, you have much to consider.   As a refresher I took a Laboratory Safety Class  from Flinn Scientific earning a Certificate of Completion (see below) for my efforts.

I was very impressed.  The presentations were very professional and incredibly thorough, and many of the narrative-styled presentations were even enjoyable.  I would recommend this course to all high-school teachers who spend time in the laboratory, and a middle-school version is also available.  Flinn Scientific did get a bigger share of my laboratory budget as a result of providing this free service, but most of the changes I made did not directly benefit Flinn at all.  See my posts on Custom Chemical Storage Shelving and on an Emergency Chemical Spill Center.

Lab Safety Certificate

Custom Chemical Storage Shelving

Partially assembled shelvingWhile overall I found myself with excellent lab facilities I found the shelving in one storage cabinet to be deficient. I took an online chemical-hygiene and safety certification class from Flinn Scientific, and that really helped me to decide the direction that I needed to go for improved shelving.  Here are some of the constraints I faced:

  1. I wanted to avoid small metal supports that  might fail upon corroding.
  2. I wanted all wooden shelves with a raised safety rail on all  sides.
  3. The shelves needed to fit in the existing cabinet without wasting excess space – meaning custom shelving!
  4. My budget was very tight!

Fortunately I used to do a fair amount of woodworking, so I decided it was time to do some wood shop despite having limited access to tools.  The partially assembled shelves may be seen here.  Notice that each shelf has a 2×4 border.  I routered a groove all the way around so that the 3/4″ plywood is supported by the 2×4 rails around the entire perimeter.  The vertical supports are 2×6 lumber which I notched to accept the 2×4 rails of the shelves.  All screws are galvanized decking screws to resist corrosion.

painted shelves   Now take a look at the painted shelves.  You can clearly see how the shelf is recessed relative to the rails on all four sides.  This prevents bottles of chemicals from slipping or rolling off of the edge.  Notice also how the rails on the shorter side have been notched in a way that corresponds with the notching in the uprights.  This adds about 2″ to the overall length of each shelf, and overall it is just a more pleasing result.  However, the notching of these rails and uprights was the most challenging part of the construction.  The grooves which were cut to support the plywood were done using a plunge bit with a router on a router table and went very quickly.  If I had a table saw or a radial arm saw available I would have made the notches using a dado blade, but alas I just made many passes with a hand-held circular saw.  That was a lot of work!

 

It was worth the effort.  See the picture of the installed shelving.  The final unit fit rather snugly in the cabinet.  This is important because space is a premium, and also it does not allow for bottles to  fall down the back or the sides of the unit.  More importantly the shelves could not collapse even if every galvanized screw eventually failed due to corrosion.  Every piece of would is supported by other pieces of wood like an interlocking puzzle, and the sides of the cabinet will not allow the pieces to slide apart.

installed shelves

ChemSketch for Science Teachers

butyneWhen teaching Chemistry or Biology (Living Environment, etc.) the preparation of professional-quality class materials can be challenging when we want to generate images of molecules.  My solution is ChemSketch from ACD/Labs.  (Just Google it!)  There is a free-ware version which may be downloaded and installed on your PC or Mac.  I am very comfortable with technology, so I was able to have it installed pretty quickly, and the learning curve wasn’t very steep.  Within a couple of hours I was able to produce quality the drawings as you see here plus many more.  I may be presenting examples that are more complex than what you need.  For people who are less confident with technology it might be nice to work together with a colleague or perhaps a technology specialist.

ChemSketch has a lot to offer besides just organic molecules.  For example, there is a library of sketches of laboratory apparatus that could be very useful for creating labs.  There is much more that I will explore in the future.

I did find one shortcoming.  I wanted to export my images as simple jpg or png files, and I could not find a way to that.  My work-around was to take screen shots which generally have poorer quality especially if enlarged.  Maybe the premium commercial version has more to offer, but the price if probably too high for a typical high-school science department. Considering the price of free I am all too willing to accept this inconvenience.

ester synthesis

To view a dry-lab exercise for working with organic compounds and functional groups Student/Chemistry/Organic Compounds.

To download a PDF version of the same  visit Teacher/Chemistry/Organic Compounds.

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