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Archive for August, 2011

8/23/11 Virginia Earthquake Propogates Across the Country

This video is courtesy of the Bad Astronomer

Watch as the seismic waves make their way across the USA. Red denotes upward motion, Blue is down.


Ghost Writer Invisible Ink Pen & UV Light

One of the more popular items we sell at Spectrum are pens that use invisible ink that only show up under ultraviolet light. The most popular ones actually have the ultraviolet light built right into the pen!

We recently added the new Ghost Writer as our latest Invisible Ink/UV light pen.

Ghost Writer

The Ghost Writer has all the features of older models but at a much lower price (under $4!).  It has the invisible ink pen, the regular pen head, and the ultraviolet led flashlight. Batteries are included!

To use it, all you need to do is write whatever you want. You won’t be able to see it of course, its invisible! But then you shine the ultraviolet light onto the paper and voila!

Invisible Ink under UV Light

Laboratory Glassware – A Primer, Part 2

Continued from Laboratory Glassware – Part 1

There are a few more flask designs to cover:

Round Bottom Flasks

Round bottom flasks are most often used for heating or chemical reactions. Their curved bottoms mean that there are no corners for materials to get stuck in,  nor hot spots or weak points to form. Round bottom flasks are often part of systems and so while many have 1 neck, others designs may have 2 necks or 3 necks! These necks often have glass joints for joining to adapters and tubes.

Since they are used for heating or must join with other glass lab systems round bottom flasks are almost exclusively made of borosilicate glass.  The big disadvantage of round bottom flasks is that they can’t stand up on a table on their own.  They require a lab system to support them or use of a flask stand.

Flat Bottom Flasks

Flat bottom flasks are round flasks, usually 1-neck, that are used for heating in distillation or other reagent reactions. They are not as durable as round bottom flasks but don’t have the sharp and vulnerable corners of an Erlenmeyer Flask.Their flat bottoms do allow them to stand up on a hot plate, shelf, or table.

Volumetric Flasks

Volumetric flasks are use to make compounds to a decent degree of accuracy (the accuracy depends on Class ‘A’ or ‘B’ quality). To ‘operate’ a volumetric flask you put the correct mass of a compound (powder, concentrated liquid, etc)  required to make a 1 molar, 2 molar, etc. mixture and then add water to the line marked on the long neck.  The long neck and stopper (every Volumetric flask should come with some kind of stopper) allow for vigorous shaking to make the mixture. Volumetric flasks can be made of glass or plastic since they are not used for reactions or heating. Plastic is less expensive but more prone to staining, and it is also not as accurate.

Filtration Flasks

Filtration Flasks are Erlenmeyer flasks with a spout for attaching a hose. That

Filtration Flask

hose runs to a vacuum pump that pulls the air out of the flask. When this happens a special funnel system (sometimes just filter paper) sitting on top of the flask. The pump pulls the liquid and smaller particles through the paper and into the flask. The larger particles get left behind on the filter. Filtering flasks need a lot of strength so they are built out of glass and have much thicker walls than their regular Erlenmeyer flask counterparts.


Continued in Part 3


Soda Bottle Water Rocket!

We’ve recently added a nifty outdoor toy: The Water Rocket by 4M.

Water Rocket

The concept is one you might have seen in smaller form: you pump up a model rocket that has a small amount of water inside. The pressure builds up a lot from your pumping and when you release the valve the high air pressure pushes the water out of the rocket. When that happens, good old Action/Reaction takes place to launch the rocket into the air.

This kit make a larger water rocket using a soda bottle and some parts to assemble it into a launchable rocket. The only thing not included is a bicycle pump – one that works a Presta valve (most do these days).

Once the rocket is assembled you pump it up and launch it up to  100 feet in the air! Please be sure to be outdoors.

This kit is a great entry into soda bottle water rocketry, don’t forget that you can buy a great instruction book to take things even further and make super soda bottle rockets!


Laboratory Glassware – A Primer Part 1

There are dozens and dozens of different types of lab glassware available to anyone who wants to buy them. But all of these different types of glassware can get rather confusing to folks so we figured is was time for a little educational post about the many different kinds of glassware than scientists use:

We’ll start with the basics.

Griffin Beakers: These are one of themost common pieces of glassware out there. They are pretty much just glasses with graduations to show much they are holding (usually in ml). They should be made of borosilicate glass (which has many brand names: Pyrex, Bomex, etc). and can go in size from 5ml up to 10,000ml. They usually have a pouring spout and are capable of holding liquids or powders. Griffin beakers are used for mixing or heating chemicals or for staging chemical reactions.

Plastic versions of Griffin Beakers are available where breakage might be a concern, but plastic is completely unsuited to some chemical reactions and cannot be used for heating.

Erlenmeyer Flasks:

A flask is different from a beaker in that it has sloping or round sides rather than

the straight sides of a beaker. In the case of an Erlenmeyer Flask they slope in a

cone shape to close towards the top of the flask. There are many types of flasks and Erlenmeyer Flasks are the most common. The narrow top allows mixing with reduced chance of spillage, and the smaller mouth can be topped with a cork, or in some designs with special joints for attachment to other lab tubing.

Erlenmeyer flasks are used for stirring or shaking where their narrow mouth openings can reduce spillage. They can be used for reactions, heating and most other functions. Erlenmeyer flasks should be made of borosilicate glass for safety purposes, although plastic versions are available for non-heating, less caustic experiments. These plastic versions often have screw on lids for vigorous shaking/stirring. The plastic used should be the more durable Polypropylene.

Graduated Cylinders:

Graduated Cylinders are used for more accurate measurement of liquids. While Griffin Beakers and Erlenmeyer Flasks may have measurement markings printed on them, they are more for general reference than accurate measurement. To properly measure liquid in quantities larger than 1ml an appropriate size cylinder should be used. Reactions should rarely be done in cylinders, and heating/shaking/stirring should not be done in them. The chemicals should be poured into a beaker or flask to do that. Cylinders are usually made of borosilicate glass, with either a 1 piece glass base  or a  glass tube inserted into a plastic base. The plastic base can make the cylinder easier to clean, but can also be more vulnerable to spilled caustic chemicals.

Completely plastic graduated cylinders are also available for those who want less glass breakage and aren’t using reactive chemicals. The plastic used can be either polyproplyene, which is translucent and can be tricky to read the measurements, or PMP which is clear but can be more expensive and more brittle.

Since graduated cylinders are used for measuring chemical quantities they have markings on them to note quantity of liquid, etc.  These markings are usually ascending but in some cases they may be ‘Double Scale’ where the 1 set of markings counts up and the other counts down. A lot of graduated cylinders just have one set of markings, however.

Most graduated cylinders sold are considered to be class ‘B’ quality. These are accurate for most purposes. More precise measurements  should use Class ‘A’ cylinders which usually has tolerances of about 0.5% for more accurate chemical measurement. These high tolerances come at fairly steep price, however.

Continue to Part 2!  More flasks and specialty glassware!


Rumble on the East Coast

OK. So we interrupt today’s blog post to tell you about a (realitvely) rare 5.9 Earthquake centered in Virginia.

We felt this guy in Philadelphia, as our building shook for a few seconds and the top floors made some odd squeaking sounds (or store is in a fairly old building).  Fortunately no damage was reported in the immediate area.  Now while some folks on the West part of this country may scoff at Earthquakes, even a 5.9 can get their attention.

In any case things seem to be back to normal around here, but there may have been some damage locally around the epicenter.


Neodymium, Rare Earth Magnets, Part 2 – Price Levelling Out

As we noted in our previous blog entry on the price of Neodymium the cost of Neodymium has skyrocketed this year due to a combination of increased taxing in China, restrictions on exports, and other causes. It has had a bit of an effect on casual use of Neodymium magnets as toys – the very popular BuckyBalls, for example is facing its second price increase this year alone. The manufacturer is reacting to the price increases by producing a lower cost product with fewer magnets.

The ‘good’ news is that is seems the price of Neodymium may be leveling out.

Graph courtesy of Metal-Pages.com

That of course is somewhat bittersweet news. This leveling out has taken place after the price has increased 3x-6x-fold depending on how you measure.

Will the price go down? Hard to say and we are lovers of science, not economists. We can say that there are signs that companies in countries outside of China are a little tired of China having such a monopoly and are taking matters into their own hands and starting mining and production facilities. We are taking these developments as a sign that prices are expected to remain significantly  higher than they used to be in the recent past for the long term. Otherwise such dollar investment in production would be a dangerous play if this were a bursting price bubble. China  says they plan to use the new tax towards new pollution controls,  and has little reason to ease its export restrictions after just a few months. Domestic companies’ production efforts are unlikely to cause a bubble burst as they will not be producing rare-earth magnets to glut-inducing levels.

One other thing to consider is that despite these massive recent increases, Rare-Earth magnets are still much cheaper now than they were in the past. A glance at a science catalog from the year 2000 (before Chinese production really ramped up) shows that a 1″ disc magnet cost $13.95! A comparable product after the recent price increases only costs just $5.99. In another comparison, a 1″ disc made of Samarium Cobalt (another type of rare earth used for magnets – less powerful but able to resist high temperatures) cost nearly $50 in 2000.

Neodymium (Rare-Earth) magnets are many times more powerful than regular magnets. They are not only used in toys, but also in hard-drives,  hybrid automobiles, and a host of other devices in our everyday life.