BW Science Labs » Physics

NASA Hubble repair mission- meeting the "Repair man" of Hubble

Brennon — Tue, 15 Sep 2009 04:37:00 +0000

During the school year time is scarce. It has to be hunted for and captured like an elusive animal. However, despite this crisis of time, I still managed to go to a three hour lecture given by astronaut John M. Grunsfeld at a local hotel. It was worth every second. Grunsfeld and his team had just returned from a mission to repair and re modify the Hubble space telescope, making this latest mission Grunsfeld’s fifth time in space. Grunsfeld modestly calls himself “the repair man of Hubble”, though I can’t think of any other repair men who attended MIT and later Cal Tech.

I found Dark Matter to be the most interesting topic of discussion tonight, and it brought me back to the good old days of seventh grade me visiting the Stanford Astrophysics and Cosmology center, and spending the entire time talking with a freshman at Stanford about Dark Matter and Energy.

Grunsfeld’s arm was in a sling, after his space suit pulled his arm when working on the Hubble recently. Essentially John Grunsfeld has achieved every supermarket shopper’s goal: having the best answer to the question you’re asked at the checkout line: “So, what happened to your arm?”.

“Oh, you know, just pulled it while replacing CCD cameras on a space telescope the other day. No big deal.”

Liam Nesson + Astrophysics = ??

Brennon — Mon, 24 Aug 2009 04:11:00 +0000

Today I noticed the release of a new mini-documentary on Hulu, narrated by none other than Liam Neeson. Black Holes: The Other Side of Infinity is a great little movie that provides a good basic introduction to black holes so the non-astrophysicist can understand the core concepts. I was happy to see that the producers included some information on wormholes and white holes as well, two important ideas that are sometimes overlooked. Its always interesting to me to see something on Einstein and his theories. His perception of spacetime (yes, one word) is incredible to say the least.

Seeing this documentary was perfectly timed for me, as I’ve just gotten around to finally reading Death by Black Hole by Neil deGrasse Tyson, who is also a Nova host from time to time. If you find this interesting, check out Brian Greene’s The Elegant Universe, the very book that sparked my interest in physics. What I really like about astrophysics is how little is really understood, and the universe is just waiting to be discovered.

Unveiling the LHC- One Giant Leap For Physics

Brennon — Tue, 23 Sep 2008 19:05:00 +0000

You may have seen the Linear Accelerator at Stanford University. If you have then you know how amazing it is, stretching nearly a mile long it is remarkable that it was build by a school. Now, a structure built by CERN will dwarf Stanford and all other atom smashers around the world.

The LHC (Large Hadron Collider) has been talked about in many books and lectures like one of my favorites: Physics of the Impossible by Michio Kaku. Now, the LHC has been built, and it more magnificent then anyone of us could have ever predicted.

Some people were supposedly worried that when the LHC was fired up for its first test the world would explode, every time I hear that I laugh out loud.

Picture Credit: Roy Langstaff, © CERN
http://www.boston.com/bigpicture/2008/08/the_large_hadron_collider.html

Picture Credit: Maximilien Brice, © CERN
http://www.boston.com/bigpicture/2008/08/the_large_hadron_collider.html

I look forward to upcoming tests, as this is a milestone in the development of Quantum Physics.

Practical Uses For The Geiger Counter

Brennon — Tue, 16 Sep 2008 18:56:00 +0000

“When it comes, will you please let your readers know what practical applications in everyday life the Geiger Counter will have? I have heard of it for years and thought it was good mainly for finding metals under the soil.”- Anonymous BW Science Labs Reader.

My Geiger Counter did arrive, but the only reason I was hesitant to immediately create a post was because the ebay seller failed to send the special headphones and the 6 dosimeter tubes as promised. The reason I can’t use any normal headphones is because the Geiger Counter I have is so old that it was a “phone” jack rather than a headphone jack. The seller has not responded to any of the emails I have sent to him requesting the items he forgot.

Furthermore, the six dosimeter tubes are still missing. Dosimeter tubes display how much radiation the wearer has accumulated over a period of time. Dosimeter tubes are checked periodically to see how much radiation they have been exposed to since its last charge. Dosimeters can also be in the form of badges that you see dentists an x-ray operators wear. The difference between a dosimeter and a Geiger Counter is a Geiger Counter tells you how much radiation your GM (Geiger-Muller) tube on the counter is picking up at one point in time. Dosimeters are better to use in a radiation lab while Geiger Counters are better for searching for radiation leaks, sources, etc.

An experiment I wanted to do with the dosimeters is see how much radiation an average person accumulates in one day going to school, work, etc. because as you read this, tiny radioactive particles are zipping through your body, however only in trace amounts. I wanted to see how much radiation there would be total. Unfortunately, I cannot do so without a dosimeter tube.

Metal detectors are typically used to locate metal (i.e. underground as the asker mentioned), but they fail to locate radioactive sources. That’s where the Geiger Counter comes in. Many houses are built on radioactive sources without knowing it. Also, something called Radon gas can inhabit enclosed areas, doing enormous long term damage to whoever lives in the house. By using a Geiger Counter you can check your home for radiation, which is pretty practical. After going through my home many times, I was “disappointed” to find nothing radioactive.

Many old watches are painted with radioactive materials to glow in the dark. Geiger Counters can pinpoint this radiation for you to clean up.

Thank you for your question, but please leave your first name later to make it easier to reply and reference.

Thanks.

Geiger Counter Delay

Brennon — Sun, 07 Sep 2008 05:06:00 +0000

My Geiger counter should have arrived on Friday, however the ebay seller’s “relative got sick”.

Ah well, at least it will come some time (hopefully this week).

The Mathematics, Science, and Future of Flight: Exploring Flight Theory

Brennon — Tue, 02 Sep 2008 02:15:00 +0000

“Can you write something about theory of flight and new navigation technology?”
This is what a BW Science Labs reader asked me a few days ago.
I am now very comfortable writing about flying as I have written many articles on the topic.
I first discovered the true basis of Flight Theory when I was 11. In Alaska, I asked a pilot to teach me to fly. It was a bolder statement than I first realized, but not at all impossible. It was then that I learned about weight (ok, when I was 11 I knew what weight was), lift, drag, and thrust.
Weight is the most obvious factor, the measure of the gravitational pull on an object, any fourth grader can tell you that. Because the plane stays on Earth during flight (excluding space ships, of course. “I’ll have to wait until I’m 16 to fly those,” I thought.) weight is a constant. It never fluctuates, though its Gs can of course. If you fly in an arc theWeightne point you will reach 0 Gs you will simulate zero gravity for a short period of time. NASA has a plane to train astronauts by taking them into a zero G environment for up to 40 seconds. NASA calls it the “Weightless Wonder” (cough*, cough* the Vomit Comet). Weight can be easily calculated using the basic equation w= mg, or Weight = Mass multiplied by the acceleration of gravity as a result of the pull between the Earth and the plane.
Lift is what keeps the plane up, and I find it more frustrating to explain. The Alaskan pilot Dan taught me that as you pull up, air particles are forced downward pushing the plane upward. This is in accordance with Newton’s third law that everything has “an equal [or proportionate] and opposite reaction”. I read another explanation years later, one a bit more confusing, but equally logical. The Bernoulli principle or effect as its called says that the shape of the wing splits the air into two parts. The air above the wing has less pressure than the air below it. Thus, the plane is pushed up not by air particles, but by a pressure difference. To this day there is still much debate over which explanation is correct.
Drag is the force that slows the plane down. Drag is also a fancy name for “air resistance” which a seventh grader can tell you about easily. The air in front of the plane resists the plane’s forward movement. Imagine running through a pit of floating bowling balls, the heavy spheres would get in your way, and you would have to push through them to continue. Though this metaphor is exaggerated quite a bit, the plane would feel similar resistance, just not on the same scale.
Finally we’re left with thrust, what moves the plane forward. Newton’s Second and Third Law are at work here. Propellers can pull the plane forward (or push if they’re on the back of the wings) by taking in air and pushing it backwards (once again, reverse the two for planes with propellers on the back).
In the title I promised to put a little something about the future of flight. In later posts, papers, and articles I will dive into depth of aerodynamics and how that will affect flight. By making plane airfoils and bodies more aerodynamic we can maximize efficiency in terms of speed and fuel consumption. I would like to see what future planes will look like. Unfortunately, I have to wait.

All data was checked for accuracy at:
http://web.mit.edu/16.00/www/aec/flight.html
and
http://www.livescience.com/technology/060828_how_planes_fly.html