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Archive for July, 2012

New Hot Plate & Magnetic Stirrers – Analog & Digital

There’s a couple of new players in the almost-obligatory-in-labs Hot Plate & Magnetic Stirrer combo unit. The new United Scientific Analog and Digital Models.

First up the Analog unit:

This hot plate/stirrer unit has a stainless steel plate with double PT sensors. Control is by two dials, one for heat and one for stirring. It can spin a stir bar from 50 to 1700 rpm and has a maximum temperature of 350 degrees C.

The digital hot plate/stirrer has even more features:

This hot plate/stirrer has a scratchproof chemically resistant coated ceramic plate. It has 1-dial control for temperature, time and speed.  Each of these has its own LED readout. The unit can spin from 50 to 1500 rpm and can heat up to 350 degrees Celsius.  The unit also features a pole with mounted temperature probe so accurate readings can be taken and the unit can shut off before a set temperature is exceeded. This feature frees up lab workers to do other things as they need not constantly monitor the temperature of the liquid. The pole system also allows the temperature to be read during vigorous stirring.
Both stirrers are ready for sale and will ship straight to your home or office.

Link to: Analog Hot Plate/Magnetic Stirrer ($279)

Link to: Digital Hot Plate/Magnetic Stirrer ($449)

www.spectrum-scientifics.com

 

Astronomy Hints #16 Reflector vs. Refractor

This astronomy hints post is going to double cover much of what we covered in our Telescope buyer’s guide but we hope to go into a bit more detail for those considering their first telescope – and that is the raging battle between reflectors (telescopes that use mirrors) and refractors (telescopes that use lenses).

Now we are just concentrating on the telescope’s optical tubes. We won’t talk too much about mounts right now. First let’s take a look at the two designs:

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Now odds are, if you are looking at these two designs and don’t know a thing about telescopes beyond what TV & movies may show your first instinct will probably be to think of the refractor (the one on the left) as being what you think of as a telescope: a tube pointing at what you want to look at while on the opposite end of the tube is the place you look into. Its very simple, and very intuitive. It even invokes the old brass collapsing telescopes every pirate move seems to be require to show by law.

Conversely, the reflector (on the right) can be a bit odd-looking. First of all, the front end is open and empty! You have to look all down the tube to see any sort of optics 013thumb(i.e the primary mirror).  Then you notice that there is no place to look through at the end of the tube. The eyepiece just kind of sticks out of the side, and the finderscope (a little telescope used to help find things in the night sky) isn’t in the same place as the refractor. What is going on here?

Well, what is going on is that while the result is the same (light gathering and magnification), and some of the fundamental optics are doing the same thing, the fact is they are both doing it very differently.
First up the refractor employs a large lens, located at the front of the tube, to refract (hence the name) or bend the light. This bent light is designed to come to form an image very close to where the eyepiece is located (you can get an idea of how this works by making an image of an object on a wall with a magnifying lens – just remember the telescope is designed to have the image form much further away!). The eyepiece then focuses on this image. In a way this is like having a magnifying glass focus on a magnified image – sort of.

Diagram of a Refracting Telescope

Conversely, the reflecting telescope doesn’t bend the light, it reflects it, or bounces it if you prefer. This is similar to what the mirror on your car or in the bathroom does, except that the mirror in a telescope is curved. So it also forms an image not very far from the telescope’s eyepiece:

Reflector Telescope Diagram.

So now that you know how each is different, the question becomes:

WHICH IS BETTER

The fact is: There is no simple answer for this. Let’s just go over some basics.

Let’s start with the advantages

ADVANTAGES

Refractors:

  • Tend to have sharper images
  • Have more traditional designs
  • Do not require much maintenance or collimation

Reflectors:

  • Are less expensive to build at larger sizes

Seems like Refractors are the winner, yes? No, not really.  You see that first advantage of reflectors is a killer. It is simply much easier to make a larger mirror than a large lens for a telescope. With a mirror, you need to polish only one side and coat it. With a reflector, you need to polish both sides at least two lenses (most refracting telescopes use air-spaced achromats (multiple lenses) and will probably need coat them with an anti-reflection coating as well.  That’s four lens sides, each one with a different curve.

The major selling point of refractors at small sizes is their traditional designs & lack of need for collimation. A small refractor will cost about as much as a small reflector and will give a beginning astronomer fewer things to worry about. The other advantage, the sharper images,  tends to only come with higher-quality refractors or even what are known as apochromatic (3 or more lenses, or two very well designed ones) objective lenses. These can get very expensive, but at small sizes (i.e. easy to transport) the refractors can easily win out with image quality. Many astronomers, not wanting to haul around heavy reflectors, may opt for these advanced refractors.

Let’s look at the other side of the coin:

DISADVANTAGES

Refractors

  • “Chromatic Abberation” – where the lens breaks up the light like a prism
  • More expensive than reflectors at mid and large sizes.

Reflectors

  • Requires occasional maintenance/collimation for ideal viewing
  • “Secondary Shadow” from secondary mirror will cause some loss in the light gathering

Chromatic Abberation can be annoying when viewing bright objects (the Moon, Jupiter, Venus, etc) as it results in what is known as a “violet fringe” around the object. This can be filtered out, and it doesn’t show up much on dim objects (light galaxies, nebulea, etc.) . But it can be frustrating to some novice viewers.  More critical to refractors is the expense of making medium and large-sized models. We already covered why in the advantages section.

Reflectors on the other hand have the problem with collimation. Most large reflectors are probably going to need collimation if they’ve been moved around a lot. They will still work if they aren’t precisely collimated, but the images will appear streaky. Collimation can be a bit tricky to master and so can frustrate novice astronomers.

The secondary issue is bit of a misnomer. What it essentially says is that any reflector telescope is not going to gather as much light as its full surface area as a portion of it will always be in the shadow of the secondary mirror. This is mostly just a nuisance as if one needs more light gathering power one simply makes a larger primary mirror., but then weight does become an issue.
So to answer the question of ‘which is better’, there really isn’t much of a straight answer – at small sizes (for beginners)  there is little reason to not get a refractor. But once the sizes get larger the reflector very quickly becomes much more economical. These rules are in no way ‘hard and fast’ as there are many exceptions to them. But as an overall guide they can give you an idea of what design to look at.

www.spectrum-scientifics.com

BuckyBalls To Be Banned?

BuckyBalls have been a best selling desktop toy since we added them over three years ago.  A bunch of spherical high-power magnets the stick together well, but can be manipulated like silly putty or made into all kinds of cool shapes.

BuckyBalls have had their struggles over that time: The biggest issue it seemed was the skyrocketing price of rare-earth neodymium used to make the Buckyballs. But it seems they were causing injuries to children too. Not the very young kids you might expect, but kids in their tween/early teen years. It seems that some kids were using the BuckyBalls to make fake tongue stud or other piercings and swallowing them. Now this might be dumb already, but then you have to consider that swallowing just one BuckyBall isn’t going to be a problem (as long as you stay away from MRI machines. You have to swallow two or more. Then they attract each other in different parts of your intestinal tract and pinch them together the intestines and cause health problems.  To date, 2 million sets of BuckyBalls have been sold, with approximately 1 dozen incidents (another dozen have been attributed to other magnets toys) that required surgery. No deaths have been caused by BuckyBalls.

The Consumer Product Safety Commission moved yesterday to ban BuckyBalls due to these cases. Despite BuckyBalls’ makers Maxfield & Oberon making efforts to prevent young  children from being sold BuckyBalls (extra packaging, voluntary recall). CEO Craig Zucker has blasted to arbitrary and unfair nature of the suit, stating “”I don’t understand how and why they did this without following their own rules before allowing us to make our case. It almost seems like they simply wanted to put our products and industry out of business.”

It should be noted that CPSC has asked M&O to cease selling BuckyBalls, which is a bit like asking Ford to stop selling cars. CPSC has also targeted BuckyCubes, a product with a cube shape instead of spherical for the same reasons as BuckyBalls, despite there being no incidents with BuckyCubes and a much lower likelihood of any such incidents due to them not resembling tongue studs. In essence, the CPSC has asked M&O to go out of business.

Stay tuned to see how this turns out.

UPDATE: Maxfield & Oberon has struck back with this reply: https://www.getbuckyballs.com/buckyballs-only-marketed-to-adults-cpsc-press-release/
www.spectrum-scientifics.com

Sally Ride, First female US astronaut, RIP.

Yesterday, Sally Ride, the first female US astronaut, and third woman in space overall, died after a long fight against pancreatic cancer.

 

Sally Ride was not the first woman in space, and she was not even the second woman in space.  Valentina Tereshka was trained in a crash course (she was a parachuter but not a pilot) and her flight was considered more of a stunt than anything else – mind you this was the era of public space stunts by the superpowers – but the lack of training and the superficial  nature of the her flight was indicative of the ‘propaganda over progress’  nature of USSR space flights that led to them to fall behind the US program. Svetlana Savitskaya was a more fully trained astronaut, but her training had started in 1980, wheras Sally Ride had been part of NASA’s astronaut program since 1978.
Sally Ride faced a higher level of scrutiny from the media due to her gender. While NASA was well past the age of  ‘male, clean-cut types only’, there was still a degree of chauvinism displayed. Sally Ride was asked once if she cried when things went wrong, some wondered if the space flight would damage her reproductive organs, some less-than-stellar experts claimed her hair (done in an 80’s style perm) would destroy everything inside the shuttle, and the question of how she would go to the bathroom in the shuttle was asked- a lot. Although to be fair ‘how do astronauts go to the bathroom in space’  is the most commonly asked question of the astronaut program, male or female.  Ride answered most questions skillfully,but pointed out the double-standard by asking “how come Rick (Hauck) doesn’t get these questions?”, and just outright not answering a couple of others.

Ride flew twice on the Space Shuttle, on flights STS-7 and STS-41-G. She also acted as the ground-based Capsule Commander for the 2nd and 3rd Shuttle flights. When disaster struck the Challenger in 1986 she was on the investigation team.  Even though she left NASA in 1987, she was asked back to help the accident investigation of the 2003 Columbia space shuttle disaster.

Once Ride left NASA, she continued to keep most of her life private while working for private companies. She acted as an inspiration to young girls in science but never pressed the issue very far – accepting her duty as a role model. But she considered herself a scientists & astronaut, not a celebrity.  She rarely exploited her fame – (a commercial for Office Depot was about it).

Sally Ride was 61.

www.spectrum-scientifics.com

 

Tie-Dye Lab Coats

OK, we’ve carried lab clothing before – protective aprons, protective sleeves, etc. But let’s face it – they aren’t exactly exciting:

wheeee…

But now there is something that will add a little spice to the labroom. We now have Tie-Dye Lab Coats!

These lab coats are 100% cotton and are colored in a vibrant tie-dye pattern! The sizes are Small (S), Medium (M), Large (L), Extra-Large (XL), and Extra-Extra-Large (XXL)

Coats feature one upper breast pocket, two roomy lower pockets, side slit openings, and an adjustable back belt.

Add some color to the lab, and get yourself a tie-dye lab coat today!
www.spectrum-scientifics.com

Mars Science Laboratory AKA Curiosity – The Landing

As of this writing, the Mars Science Laboratory is scheduled to make landfall in less than 19 days (clock countdown here).  The Mars Science Laboratory, nicknamed Curiosity, is one of the biggest rovers to go to Mars, measuring at 10 feet long (often compared to a Mini-Cooper in size). Only the Viking Lander was comparable in size and that didn’t move or do anywhere near as much as Curiosity will.

Since Curiosity is a bit of a bear, it is going to be delivered in what we consider to be the coolest method of landing a roving Mars vehicle ever:

Yeeee-Haaa!

Look like fun? The lander will need to go from 13,000 mph to zero in under 7 minutes. Sound like real fun? Well if youhave an XBOX360 and XBOX account you can actually play a Curiosity  landing game designed by NASA. It is free, just look up “Mars Rover Landing” on XBOX live. It even works with the Kinect.

Curiosity is full of equipment,that mast has a camera that covers a large portion of the spectrum, so it can see in Infrared and Ultraviolet. The camera has several filters and modes to get the best imaging. Curiosity also carries a Spectrometer, Robot Arms (with cameras), Sample analysis equipment, and much more.

Curiosity is scheduled to land on August 5th or 6th depending on your position on the planet.

www.spectrum-scientifics.com

 

 

New Hands-On Science Books

There’s some new books in town, and they are all great fun for kids. They involve hands-on science projects on a  variety of topics.

First up is the Flying Machine Book:

This books has instructions on how to build 35 different kinds of homemade rockets, gliders, helicopters and more. Soda-Pop rockets, paper boomerangs, rubber-band  powered gliders are all part of the of this 197 page book of flying fun!

Next up is the Amazing Rubber Band Cars

This book does one thing: Have kids make cars powered by rubber bands – but it does it sooo well. Kids will learn about axles, gears, pulleys, friction, tension, speed, and much more as they build a dozen rubber band powered cars out of simple materials like cardboard, pencils, old CD’s and of course rubber bands.

The Paper Boomerang Book takes a part of that first book (The Flying Machine Book) and expands on it dramatically:

Instead of just a couple of pages on boomerangs, this book goes into heavy detail on how to build working paper boomerangs! You start by building trainers and work up to distance models, etc. Chapters are devoted to boomerang theory, tweaking techniques, decoration, and throwing styles!

www.spectrum-scientifics.com