SAS E-Bulletin-- Week of July 27, 2001




compiled by Shawn
Carlson



NOTE: This last week we've had the Devil's
own time with our outgoing email. We've been receiving your mail,
but we've been unable to reply. We finally fixed the problem by
switching to an new mail server. So if you've been waiting for
a message from me, please accept my apologies for the delay. I'll
try to clean up my email correspondence log early next week. Shawn.



 



Joseph DiVerdi Donates His
Prize to Young SAS Member... Maybe You?



Joseph won the photo competition last week
with his stunning image of a sock traveling at 450 mph. But rather
than go to our Web store to make good on his $50 gift certificate,
Joseph volunteered to donate it back to SAS provided we use his
generosity to help one of our younger members get started in science.
So in Joseph's honor I've decided to give a free copy of The Amateur Scientist CD-ROM to one of our
younger members.



If you're under 18, please write one brief
paragraph (no more than 200 words) explaining what you would do
if you had access to the greatest compendium of citizen science
projects ever assembled, and send
it to me. I'll select one young person to receive the CD,
compliments of Joseph DiVerdi.



(Please note that your submissions
will become the property of SAS and we will reserve the right
to share them with members on the Web and through the E-Bulletin.)



 



Lab Notes



LN1: Truncating Numbers to a Selected
Number of Significant Figures



by Joseph
DiVerdi



Have you ever seen the output of a computer
calculation which reads something like "sample density: 5.384756584393
gm / cm^3"? Do you feel proud at your outstanding of experimental
technique or wish that you could truncate that result to a reasonable
number of significant figures?



This Note describes a simple equation which
can be used in a number of computational environments to perform
this truncation. Since an Excel spreadsheet is a popularly used
program I'll use it to explain the formula which follows:



=round(A1,(n-1)-if(A1=0,0,int(log(abs(A1))))



In this formula A1 is the value to truncated
and n is the desired number of significant figures. The formula
makes use of the integer part of the (base 10) logarithm of A1
to determine its "magnitude". For example, numbers with
an absolute value between 10.000... and 99.999... have a magnitude
of 1, while those with absolute values between 0.0001000... and
0.0009999... have a magnitude of -4. As can be seen from these
examples, the magnitude of a number is the position, in terms
of digits to the left or right of the decimal point, of its largest
non-zero digit.



The "if( )" logical test prevents
errors arising from evaluating the logarithm of zero. If A1 equals
zero then a zero is returned, otherwise the three chained functions
are evaluated.



The round function shown is an Excel function,
round(number, digits), which rounds a number to the specified
number of digits. If digits is greater than zero, then number
is rounded to the specified number of decimal places. If digits
is zero then number is rounded to the nearest integer. If digits
is less than zero, then number is rounded to the left of the decimal
point. This fairly sophisticated function can be readily emulated
in environments with only a simple round(number) function but
that's another Lab Note.



LN2: Secrets of Zone Purification



by Shawn
Carlson



One of the most useful ways to remove impurities
from a liquid is to freeze it in a controlled way. Suppose, for
instance, you want to purify some mercury you've got laying around.
You could distill it, that is boil it and then condense the vapors.
But since even a tiny concentration of mercury vapor is toxic,
it's not a good thing to be boiling in your laboratory. But a
good solution for the home scientist is to go to the other temperature
at which mercury changes state, namely it's freezing point. As
a general rule, a pure liquid freezes at a higher temperature
than a contaminated one (that's why they sprinkle salt on roads
in the winter time). So as heat is removed from a freezing liquid
the pure molecules tend to bond together first, concentrating
the impurities into the liquid that remains. So if you place a
test tube of mercury into a bath of dry ice and alcohol, the mercury
will freeze first around the inside of the tube, concentrating
the impurities into the center. If you pour off the center fluid
when about half of the volume is frozen, the mercury that remains
will be substantially purer than what you started with.



The same trick can be used to separate alcohol
and water. In fact, one of the ways in which alcohol free "near
beer" is manufactured is to take advantage of the different
freezing temperatures of water and ethyl alcohol. As regular beer
is frozen is reaches a state where the water molecules and some
of the flavorful impurities have bonded together into ice crystals.
The result is a slurry in which the solids are mostly water and
the fluid is mostly alcohol. By straining the slurry, melting
the ice, evaporating some of the water and artificially carbonating
the result, you can create something that tastes a lot like beer
but which has almost no alcohol. (An interesting experiment for
those of you who brew your own beer.)



I've heard that Native Americans used to
concentration maple sap into syrup by setting pots of the stuff
in the snow, waiting for much of it to freeze and then collecting
unfrozen liquor. A few repetitions of this procedure is said to
have created a sweet tasting syrup that is far superior to the
boiled syrup that you find on supermarket shelves. (Boiling causes
chemical changes in some of the organic molecules in the sap.)
If Native Americans did use this procedure, then zone purification
may actually predate distillation by thousands of years. (I'd
be delighted if one of our members would look into this so I can
share the true history in a future E-Bulletin. If you can confirm
that this is true, it may even be worthy of a note in a research
journal.)



I hope to purchase a house this fall with
maple trees on the property. So with any luck I'll get to do this
experiment this winter. (Actually, I suspect that vacuum evaporation,
that is, inducing boiling at low temperature by drawing a vacuum,
will prove to be a more efficient means of concentrating cold
maple syrup. And I doubt that the Native Americans were using
that technique when Columbus landed.)



LN3: Volumetric Flasks... What are they
good for?



by Shawn
Carlson



A volumetric flask looks like the unholy
offspring of a boiling flask and a graduated cylinder. Like a
boiling flask, they have large round bottoms and narrow necks.
But their necks are scribed with just a single line that precisely
marks a volume. Many times, the neck sports a red flashing, just
as graduated cylinders often do. This allows the experimenter
to measure a particular volume quite precisely, in fact, much
more precisely than one can with a graduated cylinder. But they
have no formed lips in their rim for easy pouring. Rather, the
exits of these flasks usually sport ground throats for tight glass
to glass seals.






So what are they used for? Lots of things.
For example, many experiments require one to be able to determine
some liquid's specific gravity. Sometimes you need to tell when
some purification process is finished. (See this issue's "Amateur
Scientist" re. making your own anhydrous alcohol for one
example.) Specific gravity can also give an important clue to
the identity of some unknown substance. For instance, with a 100
ml volumetric flask and an ordinary triple beam balance it's easy
to distinguish to distinguish between anhydrous ethyl alcohol
which is always safe to work with, and anhydrous methyl alcohol
which is a deadly poison. Further, some reactions require tighter
control the volume of the reactants than graduated cylinders allow.



For all these reasons, every citizen experimenter
should have a variety of volumetric flasks at the ready. These
five volumes--10 ml, 25 ml, 50 ml, 100 ml and 200 ml--can dramatically
increase the capability of many home labs.



That's why SAS is now making volumetric
flasks available to our members. So check out the fantastic prices
in the Featured Products sections below.





Photo Notes



PN1: RE Photographing Ice Freezing in
a Bottle



by Peter
Baum



[NOTE: I asked Peter, and everyone else
who submitted an image for the photo contest, to please explain
to us all how they did it. Here's Peter Baum's delightful discussion
about his project in freezing. SC]



The photograph really "begins"
with observations made while investigating the temperature profile
of a bottle of distilled water as it cools and eventually freezes.
During those experiments, I observed a roughly cylindrical core
of white ice but I first attributed its formation to the presence
of a vertical thread that held the temperature probes (Thermochrons).
An experiment soon showed that the thread was not responsible
and so the cause remained mysterious. Another puzzle emerged at
this time. When a bottle was capped, sometimes a very narrow,
clearly defined cylindrical white ice structure formed within
the narrow neck of the bottle. Now what is peculiar about these
ice cylinders is that normally dissolved gas diffuses away from
the water/ice interface until it eventually forms bubbles in the
volume where the last remaining water freezes. The resulting ice
plus air bubbles are commonly observed as a ball of white ice
within the center of ice cubes formed in common household ice
cube trays. [Another example of zone purification, see above.
SC] It was hard to see exactly how the cylinders and associated
structures resulted from this phenomenon.






The most attractive theory I had to explain
the white ice formation was that air was being trapped by ice
dendrites that are known to form intricate patterns as well as
sheets within freezing liquids. Other experiments followed including
some with straws to explore the effects of an enclosed cylindrical
space and sections of copper pipe and insulation to control temperature.
Many of these experiments produced interesting bubble patterns
that I now think of as a kind of recording of dendrite growth
patterns. Details about these experiments and their results can
be found on the Forum



I took photograph using black and white
Ilford 100 Delta Pro size 120 film at f/32. The ice is backlit
using a single strobe. I found it nearly impossible to obtain
clear pictures with the ice still encased within a plastic bottle
because of water vapor that condensed on the surface within a
second after being wiped clean.



To me, the neatest thing about this photograph
is that it represents that moment when you are suddenly struck
by an amazing discovery. When you first look at the picture, it
seems like just a simple example of ice freezing and air being
trapped in the process. It is when you start thinking about how
this would happen in detail, and how the white ice goes right
down to the bubble of water, when suddenly you realize Wow! There
is something unusual going on here!



 



Cool Project



Peter Baum isn't the first gifted citizen
scientist to study water as it freezes. Here's a fascinating classic
project based on an article published in The Amateur Scientist
back in January, 1968. You'll find the complete text on The Amateur Scientist CD-ROM. SC



An Equipment to Study Freezing



by C. L. Stong and Shawn Carlson



Edward M. Little, a senior scientist with the Arctic Sciences
Division of the Naval Undersea Warfare Center at San Diego, Calif.,
measured the pressure exerted by both freshwater ice and seawater
ice. He found that the presence of salts in seawater reduced the
pressure exerted by sea ice to a negligible amount, whereas freshwater
ice developed pressures of more than 200 pounds per square inch.
Little describes his work as follows:



"The structure of sea ice includes
'brine cells' that prevent high pressures from developing when
the water solidifies. Sea ice is about as permeable to other substances as sandstone.
Sea ice turns out to be much more permeable than freshwater ice-probably
at least 100 times more permeable.



"I made measurements of pressure by
freezing water in a two-pound coffee can equipped with a strain gauge of the rosette type. I positioned
the gauge so that the wires of grid A were parallel to the axis
of the can. The wires of grid C extended in the direction of the
can's circumference. The difference between the strains of the
two grids provided a measure of the pressure in the can. The grids
were connected in a circuit as opposite arms of a Wheatstone bridge.
For this reason changes in resistance caused by variations of
room temperature canceled each other, thus providing automatic
temperature compensation. Grid C functioned as the active gauge,
because it always had twice the strain of grid A. I did not use
Grid B in this experiment.






"The can should be pre-bulged by freezing
fresh water in it at less than 20 degrees centigrade. The circumference
and thickness of the metal are then measured as accurately as
possible. Bond the paper side of the strain gauge to the can with
plastic cement and connect the leads into a Wheatstone bridge.






"To measure the pressure exerted by
ice, fill the can with water to within two centimeters of the
top, connect the gauge to the bridge circuit, balance the bridge
with the one-ohm potentiometer so that the meter reads 0, place
the can in the freezer and close the battery switch. Make a table
of two columns, one for time and the other for meter readings.
Readings should be taken at regular intervals. At a freezing temperature
of -12.5 degrees C. a complete test run will take two full days;
at -27 degrees the run will last about six hours.



"All that remains is to calibrate the
meter in terms of pressure, a simple calculation that takes into
account the size of the can, the elasticity of the metal and the
voltage of the battery that energizes the bridge. The current
Ig that is indicated by the meter in microamperes is equal to
the excess pressure p developed in the can, multiplied by the
radius r of the can in centimeters and by the battery voltage
Vb, divided by twice the elasticity E of the metal of which the
can is made, multiplied by the thickness of the metal t in centimeters
and by the internal electrical resistance of the meter Rg. The
result is equal to the pressure (in atmospheres) per microampere
of current, as indicated by the meter. Expressed symbolically,
the relation is Ig =prVb/(2EtRg).



"The can I used with 6.2 centimeter
radius. The thickness of the metal was 0.0277 centimeters. A reasonable
value for the elasticity of steel of the kind used in most tin
cans is about 2E12 dynes per square centimeter. I used a six-volt
battery. One atmosphere of excess pressure in the can is equal
to 1E6 dynes per square centimeter. The internal resistance of
my meter is 1,000 ohms. The calibration is completed by substituting
these quantities for the symbols in the formula and doing the
arithmetic: Ig = 1E6 X 6.2 x 6/(2 x 2E12 x 0.0277 x 1,000) = 3.3
E-7 amperes, or 0.33 microampere per atmosphere of pressure. Apparatus
that differs in size from my setup can be similarly calibrated
by substituting appropriate quantities in the formula.






"I plotted relative strain against
time for each of two experiments, one run at a freezing temperature
of -12.5 degrees C. and the other at -27 degrees. Pressure corresponding
to the indicated strain was then calculated and graphed. When
making the graphs, I subtracted 0.0003 from the strain readings
of the two sea-ice recordings so that the plots for freshwater
ice and seawater ice would not overlap.



"I was puzzled at first by the graph
of freshwater ice frozen at -27 degrees C. It has many sharp peaks
that indicate abrupt changes in pressure. The explanation became
clear when the ice was melted from the can. The soldered joint
along the seam had been torn apart. Evidently when the solder
was stressed by the expanding ice, it gave way in a series of
breaks. It is possible to estimate the maximum pressure that would
have developed in an unyielding can by adding the individual peaks
of the graph. The sum indicates a maximum pressure of about 15
atmospheres, or 235 pounds per square inch.






"In spite of the experimental uncertainty,
the graphs show clearly that seawater does not behave like fresh
water when it freezes. The difference stems mainly from the higher
permeability of seawater ice. Incidentally, chilled seawater in
sealed cans makes an effective and convenient refrigerant for
preserving foods in picnic ice chests. The leftover seawater surges
harmlessly through the already frozen sea ice instead of distorting
the containers. To provide room for the expansion the cans should
not be filled to more than 80 percent of their capacity."



 



Member Feedback



Kudos!



Thanks for the great thought and travail
this new publication has entailed. It is wonderful, easy to access
and of great interest. Your effort has not been in vain.



Keep up the good work.



John Hale



Response:
Thanks John. The E-Bulletin's aren't easy to generate. But comments
like yours make it all worth while. Most people only chime in
to complain so it's really nice to hear a positive word thrown
your way. We both thank you.



Shawn Carlson and Nancy Scarduzio



Searching for F. B. Lee



Shawn,



I have been reading the Voice of the Crystal and it is great. The
author mentions the particle accelerator in The Amateur Scientist
book by C. L. Stong in the introduction. Have we made any attempt
to contact the author or is he already a member of SAS? If not
we should make an attempt to contact him because I like the way
he thinks.



Tim
Dolan



Response:
Well Tim, if you mean the author of the book, H. Peter Fredrichs,
yes he's already a member of SAS, and we're grateful to have him.
I love the Voice of the Crystal and think that everyone who likes
to think about the fundamentals of radio technology will love
it. But your letter got me thinking about F. B. Lee-- a true legend
in the world of homebrew instrumentation.



Lee's the fellow who designed and built
the particle accelerator you're talking about. In addition to
homemade atom smashers, Lee developed lots of nifty home science
techniques, including his pioneering work in inexpensive vacuum
systems by converting refrigerator compressors into vacuum pumps.
(These projects are all described in detail on The Amateur Scientist CD-ROM.) In 1960 Lee
was a chemical engineer on the faculty of Erie Country Technical
Institute in Buffalo, New York. And that is the latest reference
I have on him. I only know him through his writings, where he
only used his initials. So I don't even know his first name.



But such things are easy to find out. So
I'm hoping that some of our members will volunteer to trace this
remarkable man down and see if we can find out more about where
he is today, and if he's living, just what it is that he is doing.
Wouldn't it be great to profile him on the E-Bulletin?



So if you're willing to lend a hand, please
send me email and join the search
for F. B. Lee.



Shawn Carlson



SAS's Non-Support of Amateur Cosmology



Dear Nancy and Shawn,



I was shocked when I went to your forum
and read that you do not support "amateur cosmology".
It has taken several hours for me to calm down and begin this
message. Your restrictions have raised the following comments:





The world could use a forum for alternate
views on astronomy, and based on the many responses I have received
from my website, there are a number of alternate views. Some are
good, some are not so good. Your web site could be just such a
forum, but unfortunately you have elected to cop out on being
a leader on this issue. I can understand not being a forum for
occult and other vague interests, but cosmology and astronomy,
which after all cannot really be verified, deserve a forum backed
by your site.



I'm sorry about the tone of this message,
but I'm really upset. How can you reject the pursuit of legitimate
scientific questions?



Thank you for your time,



Jerrold
Thacker



Response: I
want to thank Jerrold for giving me the opportunity to explain
SAS's policy of non-support for amateur theories of cosmology.
Actually, the policy goes further to also exclude SAS from directly
supporting amateur theories of creation, the unified field or
experimental explorations of paranormal phenomena.



The ban on theory is to protect SAS's health
and my life. Here's why...



Back when I founded SAS, almost every working
physicist I knew had a file drawer full of unsolicited letters
from folks who had theories about deep issues in physics. Some
were from well intentioned and reasonable people who were seeking
guidance and an honest review. But quite a few were from people
who were clearly delusional. Each of these theorists apparently
fancied himself (I've never know a woman to contribute such a
letter) to be an undiscovered genius-- a person who's abilities
are so exceptional that they could solve the most difficult theoretical
problems without even having to be fully conversent with the best
thinking of the day. (Something, by the way, which has never happened
in the history of science as far as I know.) My professional colleague
thought that these people were representative of amateur scientists,
and that impression continues to make things difficult for all
groups that promote citizen science, SAS in particular. In fact,
these folks are not scientists at all. Rather I believe that they
suffer from a peculiar form of megalomania that is, as yet, unrecognized
but psychologists.



The rational folks are always a delight to speak with (and 
  judging from his Web site, Jerrold is clearly in this camp). But just try to 
  have a rational conservation with one of the undiscovered Einsteins if you want 
  a crash course in intellectual tar-babyism. They engage you ceaselessly. They 
  are incapable of honest skeptical self-assessment and refuse to accept that 
  their ideas are fundamentally flawed no matter how devastating a counter argument 
  you muster. Their last shriek in their retreat from reason is to charge the 
  reviewer with bias and being so much a part of the establishment that the reviewer 
  is unable to see the truth in their ideas. Some of these people also suffer 
  from feelings of persecution and paranoia. I once had a dapper and well-groomed 
  twenty six year old man show up unappointed at my office who, after a brief 
  exchange of pleasantries, proceeded to physically bar my exit for two hours 
  while he explained to me his theory of space, time, God and the nature of creation. 
  You should have seen his reactions to even the most gentle of criticisms. He 
  really scared me.



Now, a brief review of the papers in those
physicists' drawers reveals that they are nearly all on one of
three topics-- cosmology, creation, and the unified field theory.
All of these areas are extremely difficult and require a tremendous
commitment in time for anyone, and I don't care how smart they
are, to master. My own prejudice is that the learning curves for
these fields are so daunting that only someone who has devoted
their entire life to the subject is likely to make an original
contribution in these areas. Of course, I might very well be wrong.
But one thing is certain. If SAS accepted papers on these topics
we would be spending most of our resources dealing not with amateur
scientists, but with the mentally ill. We simply can not afford
to do that.



Of course, it also means that if some truly
remarkable person should come along, we would miss our chance
to assist that person. But my feeling and that of the Board of
Directors is that this tradeoff is necessary if SAS is to remain
viable.



In fact, despite our official position of
non-support, I still get submissions on these topics every few
weeks. About a month ago, for instance, some fellow lied to Nancy
to get me on the phone, and started telling me about a giant sphinx
that was built into the landscape near where he lived in Pennsylvania
and how it was being visited by extraterrestrials. And when I
told him that SAS couldn't help him he started shrieking "YOU
ARE THE ENEMY OF TRUTH, YOU ARE THE ENEMY OF TRUTH!" over
and over into the phone.



Since I'm the one sitting in the cross hairs, I must continue 
  to insist that SAS do everything possible to gently discourage these people 
  from fixating on us, and especially on me and my family. And that means that 
  SAS will not accept papers on cosmology, creation or the unified field. I do 
  hate to disappointed anyone. But if you are disappointed, I hope at least that 
  you can understand our reasons and support this decision.



Our non-support of paranormal research is
for a completely different reason. After one hundred and thirty
years of experiments no one can yet demonstrate any repeatable
paranormal effect whatsoever under conditions that preclude cheating.
The field is so experimentally bankrupt that most professional
scientists see people who get too interested in it as a bit odd.
With file drawers full of "theories of everything" coloring
their views about amateur scientists already, the Board felt that
SAS didn't need to raise more hackles. And so we do not do research
into the paranormal. If that is an interest of yours, I strongly
suggest you go to the James
Randi Foundation or to CSICOP.
They have plenty of expertise and would be delighted to help you
to great science.



Shawn
Carlson



 



SAS News



Joseph DiVerdi Takes the Helm on Local
Chapters



This week Joseph
DiVerdi activated as the new head of our Local Chapter Development
committee. This week he's started by reviewing the excellent preliminary
draft of a manual for Local Chapters originally developed by SAS
member Charles Burgess. Joseph's first task will be to complete
the development of these materials into a working manual that
anyone can use to help start a local chapter in their area. More
soon.



SAS -- Tinkers Guild Consolidation



We'll, as I write all the worldly belongings
of Sheldon and Denise Greaves are bouncing along on pallets sitting
in the back of a truck headed for Rhode Island. Drs. Greaves will
arrive personally this Monday to take possession of their new
home so next week Sheldon will be here to open up Tinkers Guild
in the offices immediately adjoining SAS's. It's been a long time
in coming, but it's finally about to happen.



It's going to take a little while to settle
in and get Tinkers Guild fully functional, but I'm telling you...
we're going to own this state!



Update: The Amateur Scientist's Workshop



This week Elizabeth Rollins has been working
on our preliminary proposal for the National Science Foundation's
Informal Education Division. It's due next week. I've also started
some conversations with potential funders. More soon.



Position Papers a Non-issue



Apparently the idea of SAS issuing position
papers is either of no interest or everyone agrees and so no one
bothered to voice their approval. Only a few of you took notice
of the procedure I offered last week to keep the
process fair, open to all, but something that we can bring to
a conclusion fairly quickly. Unless I hear dissent, I'll go ahead
and propose to the Board that those procedures be formally adopted.
Then we'll move forward on our first position paper, which Sheldon
Greaves has offered to write re Maureen Clemmon's project to demonstrate
that ancient Egyptians used kites to do much of their heavy construction.
(You can check out the discussion about her work on the SAS Forum.)



 



Featured Products



Glassware Galore



I've been bargain hunting for months now
and have spent over three thousand dollars stealthfully buying
up lots of glassware to help equip your home laboratory, so boy
am I going to look stupid if you don't buy some!



We've got boiling flasks aplenty, volumetric
flasks to die for, graduated cylinders new in the box, reagent
bottles, bushels of culture tubes, thousands of graduated pipettes,
Ernlynmeyer flasks up the wazoo, condensers of all descriptions,
antique retorts, vacuum filtration flasks, ampule and sample viles
and a bunch of speciality items that I can only guess at, and
one all-glass crazy straw (really!). We've even got all kimax
5 gallon carboys of the kind that you beer brewers out there would
die for. And it's all yours for a tiny fraction of the retail
cost. Note that none of the prices below include shipping costs.



NOTE: IF YOU WANT GLASSWARE--- It isn't
on the on-line store yet. So take a note of what you want and
let Nancy know. She'll be happy
to get this stuff out of her office, believe me!



5-gallon Kimax Carboys



I have two, new in the box. These retail
for $250 each but they are yours for $99.95 + whatever
it costs Nancy to ship it to you. ID of the stopper hole is 2
1/4 inches. Kimax is borosilicate glass. These won't shock when
you pour hot liquids into them. (Like I said, a beer brewer's
dream!) No photo, you can picture what a clear 5 gallon bottle
would look like, right?



Boiling Flasks



Enough to last until rapture. Flat bottoms,
round bottoms, and even those tear shaped bottoms (that name of
which I just can't recall at the moment) that are supposed to
provide better heat conduction when being heated in a flame. We've
got a range of sizes of these, including two as large as 800 ml
in new condition, and sizes of the round bottoms going from 50
to 1000 ml. Most are new, some are like new. And a few could stand
an hour in an ultrasonic bath. New and like new items, 50 percent
off. The used one's you can have for 60 percent off. Cost of like
new items (not including shipping).






100 ml (flat or round) ring neck -- retail:
$4.00, Member Price $2.00 each



200 ml (flat or round) ring neck-- retail:
$5.00 Member Price $2.50 each



250 ml (flat or round) ring neck-- retail:
$6.00 Member Price $3.00 each



 



Distillation Flasks



A distillation flask is a boiling flask
with a long downward sloping arm. You thread a stopper on the
arm and use it to connect the flask to your distillation column
to convert the steam back into liquid.






125 ml-- retail: $11.00, Member Price: $5.50
each



200 ml-- retail: $22.00, Member Price: $10.00
each



1000 ml-- retail: $65.00, Member Price:
$28 each (limited quantity!)



Distillation Columns: West Type



Use this to recondense steam into liquid.
Requires Tygon tubing (get it at any hardware store) to connect
to sink. Flowing water cools the inner jacket and condenses the
steam.



 






450 mm overall length with 24/40 ground
joints (bottom joint not shown in picture)-- retail: $70.00, Member
Price: $35.00 (limited quantity!)



Distillation Column: Improved Snyder
Type



Used in reflux columns where the solvent
is returned to the boiling flask while volatils with higher vapor
pressures escape up the column. Can eliminate the need to redistill
for higher purity. The picture shows a unit with two reflux chambers.
Our condensers have three!






250 mm length, 3 chambers-- Retail: $91
Member Price: $45 (We only have three of these!)



Seperatory Funnels



Use these to collect volatile oils from
rose, pine and petroleum and other complex organic sources. The
oils separate by density to form layers inside the funnel which
are drawn off one by one using the stopcock. Limited quantity!






60 ml, pear shape with glass or Teflon stopcock
-- retail: $65 Member Price: $32



125 ml, pear shape with glass or Teflon
stopcock-- retail $72 Member Price: $35



Volumetric Flasks



We've got a stock pile of like new volumetric
flasks from 1 to 500 ml. Many have ground glass throats and stoppers
for handling volatile liquids. There yours for at least 50 percent
off the retail price.






10 ml -- retail: $18.00 Member Price $8.00



25 ml -- retail: $20.33 Member Price $10.00



50 ml -- retail: $21.66 Member Price $10.50



100 ml-- retail: $23.50 Member Price: $11.00



200 ml-- retail: $26.75 Member Price $13.00



Or get the complete set of values from 10
to 200 ml for just $49.95.



500 ml (square body) -- retail: $35.83 Member
Price $17.00



And Lots Lots More!



I'm running out of day here on Friday, so
I'll add substantially to this list next week. But don't wait
to get your order in. We only have a few of most of these items
so reserve what you want right away!



BOOKS



An Introduction
to the Study of Insects, sixth edition



by Donald J. Borror, Charles A. Triplehorn
and Norman F. Johnson 

Hardbound; 875 pages, with illustrations, drawings and photos
throughout.  

List Price: $103.00 (Amazon.com Price:$97.50) 

SAS Member Price:$92.70



If you really want to deal with those cockroaches
in your kitchen, just hit 'em with this! This is most widely used
college and reference text in entomology. Perfect for the amateur
who's really serious about a bug's life.





  

This book uses a taxonomic approach to introduce students to the
science of entomology. It's all here. Extensive use of identification
keys acquaints individuals with all the families of insects in
the United States and Canada and provides means for students to
identify 95% or more of the insects found occurring in North America.
Contains keys for identification of all the families of insects
occurring in North America north of Mexico and keys to some subfamilies. 



Provides detailed insect family descriptions,
data on anatomy, physiology & development, behavior and ecology,
nomenclature, collecting, preserving and studying insects. References
at the end of each chapter, glossary, and 67 page index. 

A bit pricey, but really worth it!



 



Chemical Demonstrations-- A Handbook
for Teachers (and lovers) of Chemistry



by Bassam Z. Shakhashiri



The most complete collection of chemistry
demonstrations to delight the student, teacher or anyone who loves
chemistry. (And since you can buy all your chemicals and glassware
from SAS, there's nothing to stop you from trying any of these
delightful and educational demonstrations. Remember, email
to chemical needs to Nancy and she'll figure out how to take
care of them.)






In this series of practical handbooks, Prof.
Bassam Z. Shakhashiri and collaborators describe a wide range
of demonstrations for displaying chemical phenomena in science
classrooms at all levels. The demonstrations are grouped into
topical chapters, and each chapter includes an introduction which
provides information about the concepts, terminology, and principles
related to the demonstrations. The demonstrations themselves are
divided into seven sections:





You can find the content of each book by
following the links: Vol 1, Vol 2, Vol 3, Vol 4. We're selling each book to SAS members
for just $27.96. Follow the above links to purchase the individual
volumes. Or, you can purchase the entire set for just $99.95 by
sending email to Nancy. Reserve
your set today!



 



A Parting Challenge



Can You Explain This. . . About Salt?



One: This
one's not too hard to figure out. When table salt dissolves it
can lower the temperature of water a degree or two. Do you know
why? Other salts are more effective. A good freezing solution
can be made by dissolving in fresh water sodium thiosulfate (the
photographer's "hypo"). The temperature of the solution
can drop as much as 25 degrees Fahrenheit. To demonstrate the
effect, wet the bottom of a thin glass container with fresh water,
stand the container on a base of wood or some other material that
is a poor conductor of heat and fill the container with equal
weights of water and hypo. Stir the mixture with a wooden stick
for a minute or two. The wet bottom will freeze and the glass
will stick to the base. A stoppered vial of fresh water placed
in the water-hypo solution will also freeze. If the vial is full,
the expanding ice may exert enough pressure to break the glass,
fresh water having the unusual property of being denser as a liquid
than as a solid.



Two: This
one's a bit harder. It's cool physics that makes for a great party
trick. Float an ice cube in a glass of water. Have a shaker of
salt within arm's reach. Hand a volunteer a paper match (unburnt,
of course) and challenge them to remove the ice cube from the
water without lifting it with any implement other than the match.
When they give up, bend the head of the match to a right angle,
place the body of the match flat on top of the ice and cover it
with a thin layer of salt. The match will promptly freeze to the
cube. Lift the cube from the glass by the head of the match. Try
it and see!



Why? Sorry, you'll have to wait for the
explanations until next week.