Sciencemadness Discussion Board - New High School Teacher looking to outfit a classroom

New High School Teacher looking to outfit a classroom

Stifle - 7-12-2008 at 12:10

Hey everyone, first post here.
I am a first year Chemistry teacher at a high school here in the states and I have been tasked with outfitting the chemistry program at our school with the basics for conducting laboratory activities.

A few specifications on the classroom before I ask for some help.
-Each class will not far exceed 20 students
-The classroom does not have natural gas lines installed yet, and probably will not this year

Now, the point is, I would like some pointers from anyone who has taught chemistry to secondary students before, I need to know what general purpose items i should try to get a hold of. i will post a list of what i have so far, if there are any suggestions on top of that list they would be most appreciated.

Cleaning/Maintenance
12-Bottle Brush, 11.5 inches x 1.5 inches
12-Test Tube Brush, 7.25 inches x ½ inch
Glassware Detergent concentrate
8-Wash Bottle, LDPE, 250ml

Glassware
6-Glass Droppers
12-Glass Student Graduated Cylinder, 50ml
12-Glass Student Graduated Cylinder, 10ml
12-Pyrex Beaker, 50ml
12-Pyrex Beaker, 150ml
12-Pyrex Beaker, 400ml

Miscellaneous items
12-Magnetic Stir Bar, Octagon, 1 x 5/16 inch
12-Magnetic Stir Bar, Octagon, 1-1/2 x 5/16 inch
6-Porcelain Mortar/Pestle, 80mm
30-Clear Glass Stir Rod, 6 inch
12-Thermometer, 0-230°F, 12 inch
12-Std. Stem Funnel, 100mm
~150-Disposable Pipets
12-Scoopula, Stainless Steel, 6 inch
12-Beaker Tongs
pH Paper, 1-14 range, 15 ft. roll
Red Litmus Paper
Blue Litmus Paper
4-Digital balances in the $75-100 range - centigram or better sensitivity
1-Digital balance in the $150-$200 range, -milligram or better sensitivity

If possible, what are some online vendors that would have most if not all of these items available? Or should i look for a local supplier? any input would be appreciated

[Edited on 7-12-2008 by Stifle]

Saerynide - 7-12-2008 at 20:22

Don't forget burets

Highschool chem labs always involve doing a ton of titrations (I don't think there was a single lab in AP Chem that didn't involve titrating something)

As for vendors, Fisher and Sigma will have everything for sure. Though other vendors will be cheaper (ebay for example)

[Edited on 12/7/2008 by Saerynide]

UnintentionalChaos - 7-12-2008 at 20:39

If you have any control over the labs you will be doing, I urge you to avoid severly quantitative things like titrations (one or two is alright). I get the feeling that nothing kills interest in chemistry for people early on like lots of calculations. Basic concepts are often well demonstrated qualitatively.

I was not in an AP chem class, but our teacher was very old school. dehydration/hydration of cobalt salts, burning of magnesium (closed crucible, then weighed. Formula experimentally derived from weight gain. reduction of copper sulfate by zinc metal, followed by HCl treatment to remove excess zinc. Demonstrations were penny in nitric acid, ignition of paraffin wax fumes by heat of freezing molten parrafin, burning sulfur, etc. Colors, and fire is good :cool:

Stifle - 7-12-2008 at 20:49

I have complete control over labs, I appreciate your comment UnintentionalChaos, and I agree wholeheartedly. I would like to get burets and stands, at least 7 or 8 (3 students per buret) but I am not sure i can get a hold of them right now - the good ones - independant teflon stopcock and pyrex 50ml - are upwards of $60 each.

UnintentionalChaos - 7-12-2008 at 21:16

Quote:

Originally posted by Stifle
I have complete control over labs, I appreciate your comment UnintentionalChaos, and I agree wholeheartedly. I would like to get burets and stands, at least 7 or 8 (3 students per buret) but I am not sure i can get a hold of them right now - the good ones - independant teflon stopcock and pyrex 50ml - are upwards of $60 each.

Wow. Then my class A pyrex w/ teflon stopcock buret was a total steal off of ebay for $13.

As for scales, I don't think you'll find 1mg or better for under $200. Scales get exponentially more expensive as you add digits. I would have bought one by now at that price. you might want to try unitednuclear.com for the other scales. They don't seem to be the cheapest, but appear to be no-bullshit unlike most other suppliers With a 200g max capacity (more than sufficient for classroom experiments), their $59 model fits your description. They are unfortunately on backorder as of now.

A few ebay stores sell bulk glassware/equipment from closed labs it seems. You may want to look, as the stuff is new, but cheaper than any supplier will have it for. I was drooling over some teflon beakers a while back, but 2 dozen of them are not in my budget.

[Edited on 12-8-08 by UnintentionalChaos]

Swany - 7-12-2008 at 21:46

Quote:

Maybe plastic ones? We have plastic ones at our high school I think. Biurets can easily meet their end in a high school lab. Plus, the acid/base solutions used will be pretty senile, whats not to love about plastic?

Stifle - 8-12-2008 at 05:04

i suppose due to my lack of experience with plasticware i have not thought of a plastic buret...

Stifle - 8-12-2008 at 05:09

looks like acrylic burets are around $50 new at fischer... better than 65 and more rugged for a classroom for sure

Lambda-Eyde - 8-12-2008 at 10:10

You've added stirbars to your list, but I can't see any magnetic stirrers?

As for the weights, I reckon a precision of 0.1g is accurate enough for most lab work, but a pair of 0.01 and/or 0.001 precision weights would be handy as well. I can't see any test tubes on the list? Better get a couple of hundred of those.

And don't forget stoppers!

As for the gas, why don't you get the type that runs on separate boxes? This type is the most used in Norway, and I prefer them over a clumsy thing attached to a hose any day!

Does the lab have a fume hood/fume hood system?

Stifle - 8-12-2008 at 11:02

I think what i am struggling with the most right now is what solution should i pursue as far as heating appliances. the classroom does not have gas and will not have it this year but i am currently teaching chemistry and some future labs will require that I heat up solutions obviously.

I did forget to mention the items which i already have, most notably

5 - single element, counter-top rangette (http://www.centralrestaurant.com/centralstore/images/stdimag...)
24 - 250ml Erlenmeyer flasks
~150 - 12mm x 100mm test tubes
some misc plasticware that is in bad condition
lots of petri dishes

I am not happy with the idea of heating up glassware on an electric element without any heat dispersing medium between them - on that note, what could i use as a medium to spread out the heat so that i could use these kitchen appliances as a makeshift hotplate?

The classroom does not have a fume hood installed yet, I have requested of the architect that he come up with a way to install one in the room and he seemed hopeful that one could be installed in a particular corner of the room, however this is the only classroom in the school that would ever warrant one, as well as the only classroom without carpeted floors...

Stifle - 8-12-2008 at 11:44

Also has anyone ever used a Boroflo stopcock on a buret before? they look like this:
http://cynmar.com/images/items/zoom/11520659.jpg

How do they compare with the classic T style stopcock?

octave - 8-12-2008 at 14:37

I've always heard that stopcock style called rotaflow but have never had personal experience with one. Add volumetric flasks to your list of things. I haven't seen it mentioned yet and in AP chemistry we relied on volumetric flasks heavily for prepping solutions.

Contrabasso - 8-12-2008 at 14:48

Rather than a list, my idea is: Look at past practical exam papers and have enough kit for all your students to sit the exam fully equipped. Now realise that this will be at the end of a year so you will need as much again for breakages. Look also at the chemicals that your syllabus needs and the reactions that need to be done. Consider buying as much as possible in bulk. -Cases of test tubes not tens.

Look also at chemical and apparatus security! I suspect that several school labs lose things to "home" scientists.

Is there a school lab wholesaler in your area, or supplying your area? There is an educational supplier in Canada and one in the UK so I'm certain that there will be one in the USA. They would have the kit at the right accuracy/price point for good results on a fair budget.

[Edited on 8-12-2008 by Contrabasso]

ordenblitz - 8-12-2008 at 16:48

Stifle,

I recommend you check out this supplier. Very decent prices on chemicals and they also have a small asst of lab items. I have dealt with them in the past, they are very easy to work with and coincidentally they happen to be close to you.

http://www.hvchemical.com/

[Edited on 9-12-2008 by ordenblitz]

CrapScientist - 8-12-2008 at 20:29

I know I mentioned this already but I think it should be mentioned again in this thread:

First check the book "Illustrated Guide to Home Chemistry Experiments" by Robert Thompson. Its got a bunch of really awesome experiments that are both interesting, fun, and relevant to the course.

He's also organized a special deal with Elemental Scientific for the stuff you'll need at great prices. If more is needed you can easily add it a la cart on the Elemental Scientific order form. Even if you dont plan on using the book, you can still benefit on the deal by outfitting your class with the kits they put together. Or vice verse, you dont need to buy the kits but you can still use the book for lab ideas. Here's a link to the kits:

http://homechemlab.com/sources.html

starman - 9-12-2008 at 02:02

I know that the US is holding out against the metric system but surely for chemistry thermometers in degrees celsius are far more appropriate.Why bother with a completely obsolete convention? All modern science uses deg C,all modern chem literature is deg C , lets get deg F out of science classrooms.

Stifle - 10-12-2008 at 07:32

i don't plan to ever measure temperature in the laboratory using Fahrenheit.

Ordenblitz thank you for that reply, my father is an analytical chemist and he uses high valley chemical and has for years.

Crapscientist thank you for that link, i had browsed that site in the past and was interested in using it to get an assortment of chemicals that would open up my possibilities for labs

Stifle - 10-12-2008 at 08:31

those balances would be great though they can only be purchased using Paypal - my school does not use paypal so I would have to front the money for the balances - as I am an educator, $250 up front is problematic.

i found another outlet that ssells the same balance for less and accepts credit cards so ill be getting 3 of those.

[Edited on 10-12-2008 by Stifle]

starman - 11-12-2008 at 02:54

Quote:

Originally posted by Stifle
i don't plan to ever measure temperature in the laboratory using Fahrenheit.

Going to have to replace those thermometers you have listed under miscellaneous items then.

Phosphor-ing - 11-12-2008 at 08:25

You will need some kind of container, probably metal, and an oil or sand for the oil bath/sand bath those single element rangettes will require. Heating glassware on those elements is way too risky for a classroom environment.

benzylchloride1 - 11-12-2008 at 15:24

i would recommend purchasing analytical balances that are good to .1mg. The older mechanical type like i use at home can be purchased off of Ebay for under $50.00. They work great but they often need to be adjusted. I have an old Mettler balance. I would recommend doing more synthesis experiments then quantitative experiments at the high school level. Just like a previous post stated; math turns most students off towards chemistry.I would recommend introducing students to the wonders of chemistry before the math of chemistry. i am a 3rd year undergraduate chemistry student and my home chemistry experimentation has played a major role in my decision to major in chemistry and continue on to graduate school. I would recommend doing as many labs as possible; labs are the most important part in getting students interested in chemistry.

Stifle - 12-12-2008 at 06:38

I found a website that sells 200g capacity .01 gram accuracy with lifetime warranty's for under $100 each. I plan on ordering 3 of them

octave - 12-12-2008 at 15:56

In my experience it is best to get a scale from a well known brand like Ohaus or Mettler Toledo. A lot of the time brand names are more expensive and all you get is the fancy name to carry with your instrument, but with scales the brand name gets you the instrument backing that brand name in well known accuracy.

Saerynide - 12-12-2008 at 16:09

About the old mechanical Mettler scales, though they are totally awesome and can in theory measure accurately to the 10 ug, they are VERY hard to keep calibrated... unless they rest on a concrete block AND you never move or accidently knock on them... The slightest disturbance will send then display flying

I cannot trust mine to read accurately past 0.01 g as a result :mad:

I decided to reinvest in a digital balance with only 0.1 mg resolution

EDIT: And don't bother with the "American weigh" or "My Weigh" scales (or any of those non-scientific brands. They are suck and are a total waste of money. They drift A LOT. You can measure something 5 times, and each time, it could differ by 5-15 mg, or even several 0.01 g's

[Edited on 12/12/2008 by Saerynide]

Stifle - 14-12-2008 at 08:18

What is your experience with My Weight Scales Saerynide? These will be primarily for students to use, and purchasing a more expensive model with a name brand as Octave has suggested would most likely double my cost for the same level of readout "accuracy" (to the mg).
If they do indeed drift then maybe i can use that to further reinforce the accuracy vs. precision concept... Teacher's mind at work...

Saerynide - 14-12-2008 at 11:45

For the American Weigh scales, Ive tried both:
American Weigh DIA-10 Digital Carat Scale 50x0.01ct / Milligram: http://www.americanweigh.com/product_info.php?cPath=60&p...

and

American Weigh Gemini-20 Portable Milligram Scale 20x0.001g: http://www.americanweigh.com/product_info.php?cPath=60&p...

For My Weigh, Ive tried My-weigh GemPro50 Jewelry Scale: http://balance.balances.com/scales/870

All 3 times, I had to send them back to the seller. Maybe their larger capacity scales will be more accurate and precise, but I can vouch for sure to stay away from their mini scales - they have no accuracy or precision.

Several times, I've tried putting 3-4 mg of material on them and they will often register nothing. The American Weigh ones were so ridiculous as to measure the calibration weight wrong every time even after calibration (I had previously measured the weight in my research lab to the 0.1 mg, so I know what it *should* weigh).

Stifle - 15-12-2008 at 12:53

that sounds pretty bad. accuracy would be top of the list on my priorities for these scales so I guess ill have to find some other brands to use.

zed - 15-12-2008 at 15:36

Burets appear to be overpriced. Want to do some titrations? Use disposable syringes.

They are graduated, easy to control, hard to damage, and are very inexpensive. If you are concerned about the pointy ends of the needles, just cut them off.

Syringes work equally well, as graduated cylinders.

Burets and other chemical glassware/plasticware are specialty items. Naturally spendy.

Disposable syringes are not specialty items, they are produced in all sizes, on a vast scale. Diabetic supply companies/clubs sell them dirt cheap.

Lambda-Eyde - 16-12-2008 at 00:58

Zed: I think a school easliy can afford burets, and IMO they are superior to plastic syringes when it comes to titrations. There's a reason professional labs don't use syringes, you know.

undead_alchemist - 16-12-2008 at 11:53

The company that I work for has pretty good prices on both ASTM Class A, and ISO DIN Class B Burettes.

How about a micro scale 1ml, 2ml or 5ml Class B??..

zed - 17-12-2008 at 01:48

No point in spending big bucks on burets for a high school chem class. Cheaper is better.
Ideas are the important thing, not pin-point accuracy.

My experience with burets at the college level was that they were extremely mortal. They are long, awkward, and fragile. Easy to break and expensive to replace. Students would break them, then be aghast at having to pay the high replacement cost. The presence of a stopcock sends the price soaring.

In simpler times, to keep costs down, many schools used burets that had a nipple at the bottom end. Slip a piece of latex tubing over the nipple, stick a tightly fitting glass bead inside the latex tubing, then insert a piece of finely pointed glass tubing at the bottom.

Squeezing at the bead, buckles the latex tubing and allows liquid to flow. Stop squeezing, and the tubing snaps tight again. Just as accurate as a stopcock, at a vastly lower price.

[Edited on 17-12-2008 by zed]

dapper - 17-12-2008 at 08:01

oldwillknott.com for scales - great prices, fast shipping

nitric - 26-12-2008 at 02:51

as for heating if you would be allowed(lack of natural gas lines) use propane tanks, easily you could set up them and they would be refillable, even though electric is good for most applications in a lab, it would at least be on hand if Bunsen burners were needed

orbit_research - 20-1-2009 at 12:39

I am selling some Jones reagent- great for visual aid for changes in oxidation states Cr(VI) red to Cr(III) green
see ebay item 190281558976