recently, my brother (and some friends) went on a camping trip in the high wilderness of Jersey. among the many pictures he showed me, I noticed a few shots of quicksand.
aside from seeing quicksand in video games and movies, I knew very little about how it worked. thankfully, I was enlighted by bill nye, the science guy.
interestingly enough, Bill asserts that quicksand will not "suck you down and make you disappear," but that drowning is an impossibility "ya wouldn't drown!" his explanation is that quicksand is simply a heavily concentrated mixture of sand and water--sinking in quicksand is as natural as sinking is water. all one needs to do is lie on his/her back, and wait minutes, days, or years for the next guy to come and save you.
just to check up on Bill Nye's claims, I found a source which stated something similar. pretty interesting!
"One of the most common reactions once a person finds his or her foot stuck is to shift weight to the other foot. At this point, a sort of seesaw motion happens -- with the person alternating their weight back and forth, trying to get a foot out of the quicksand. This movement actually worsens the predicament. What you should do instead is fall forward and try to spread the weight of your body over a large area of ground. Continue to work at freeing your foot, using slow motions so that you don't work your foot in deeper. Once you've pulled your foot out, roll away from the area, jump up very quickly and sprint to solid ground.
There have been many cases where people have gotten their legs trapped in quicksand and haven't been able to escape on their own. The sand has to be at just the right moisture for this to happen and the person has to be at least thigh-deep with both legs. Extricating a person from this takes at least two passersby, if not a full-fledged rescue team."
wow. lots of physics here. first, by shifting weight from a foot already locked into the ground to a different foot, the only thing one accomplishes is pushing the "other" foot harder into the ground. clearly, that will not work!
next, the source suggests spreading the weight of your body over as much area as possible. This is good advice to not only individuals stuck in quicksand, but people learning how to swim. spreading one's body over the water increases the amount of the body which is submerged, resulting in a greater force downward into the water. however, according to archimedes's principle, an equal and opposite force in magnitude (buoyant force) will keep you afloat. thus, spreading out your body, not struggling with your feet, will help you survive a quicksand attack.
finally, your success in the encounter with quicksand depends largely on how "concentrated" the quicksand is--the ratio of sand:water. While quicksand is normally much more dense than water, some breeds of quicksand probably contain high concentrations of water. Meaning, it would be a lot harder to float, and a lot easier to drown. The same effect can be observed when swimming: extremely salty water is much easier to float in, as highly concentrated salt water is much denser than fresh water.
so, if you ever encounter quicksand on your date with life, think:
1st) fluid mechanics--first, archimedes' principle, second, density.
2nd) get your phone and all electronics out, NOW.
3rd) if all else fails, you need to wait for some random dude to come help you. don't worry, if I ever see you stuck in a puddle of quicksand, i'll call 911 for sure.
source: http://science.howstuffworks.com/quicksand-sinking1.htm
Sunday, April 25, 2010
Monday, April 19, 2010
The Greenest Technology Company on the Planet
September 24, 2008
“Our customers have made it clear that they want the greenest technology possible,” Jeff Clarke, senior vice president, Dell Product Group said during the company’s mobility summit in Monte Carlo today. “As an industry, we can shape the future of green innovation and significantly reduce the carbon footprint associated with mobile computing. Dell is committed to leading the transition to energy-efficient LED technology.”
The "LED technology" which Clarke speaks of is none other than a light-emitting diode.
A light emitting diode is essentially a two-layered semiconductor—-it has both a p-type and a n-type semiconductor in a circuit. While current flows through the semiconductors, electrons from the conduction band of the n-type move towards the holes present in the p-type. As a result, the energy of the electron drops, and a photon is released with energy equivalent to the energy difference between the conduction to valence bands.
Fast forward to today, where owning a LED laptop is no longer an uncommon feat. This is great news for the environmentalists, as the benefits of LED technology seem endless:
"In addition to being mercury-free and highly recyclable, LED displays deliver significant energy savings compared to cold cathode fluorescent lamp (CCFL) technology. For example, Dell’s 15-inch LED displays consume an average of 43 percent less power at maximum brightness, resulting in extraordinary cost and carbon savings. The company estimates customer savings of approximately $20 million and 220 million kilowatt-hours in 2010 and 2011 combined, the equivalent of annual CO2 emissions resulting from energy use of more than 10,000 homes1."
I applaud Dell and its management in attempting to become the "Greenest Technology Company on the Planet."
source: http://www.dell.com/content/topics/global.aspx/corp/pressoffice/en/2008/2008_09_24_rr_000?c=us&l=en
“Our customers have made it clear that they want the greenest technology possible,” Jeff Clarke, senior vice president, Dell Product Group said during the company’s mobility summit in Monte Carlo today. “As an industry, we can shape the future of green innovation and significantly reduce the carbon footprint associated with mobile computing. Dell is committed to leading the transition to energy-efficient LED technology.”
The "LED technology" which Clarke speaks of is none other than a light-emitting diode.
A light emitting diode is essentially a two-layered semiconductor—-it has both a p-type and a n-type semiconductor in a circuit. While current flows through the semiconductors, electrons from the conduction band of the n-type move towards the holes present in the p-type. As a result, the energy of the electron drops, and a photon is released with energy equivalent to the energy difference between the conduction to valence bands.
Fast forward to today, where owning a LED laptop is no longer an uncommon feat. This is great news for the environmentalists, as the benefits of LED technology seem endless:
"In addition to being mercury-free and highly recyclable, LED displays deliver significant energy savings compared to cold cathode fluorescent lamp (CCFL) technology. For example, Dell’s 15-inch LED displays consume an average of 43 percent less power at maximum brightness, resulting in extraordinary cost and carbon savings. The company estimates customer savings of approximately $20 million and 220 million kilowatt-hours in 2010 and 2011 combined, the equivalent of annual CO2 emissions resulting from energy use of more than 10,000 homes1."
I applaud Dell and its management in attempting to become the "Greenest Technology Company on the Planet."
source: http://www.dell.com/content/topics/global.aspx/corp/pressoffice/en/2008/2008_09_24_rr_000?c=us&l=en
Monday, April 12, 2010
Dynamic Systems
for those of you reading this at school (and can only read this at school; owned!), I'm not sure if flash games are surf controlled, so I apologize in advance.
I struggled for awhile to find something in my house related to nuclear physics, so I decided that really, it wasn't worth the effort. I'd have to find something else. While procrastinating, I stumbled upon this nifty game thing called 'dynamic systems.'
The game is extremely simple at first, but gets exponentially harder within the first five levels. The idea is simple: initially, a silver ball is present on the board, somewhere far, far, away from the bucket. Using the random assortment of tools provided and properties of physics, one must place various objects which, when the ball is set into motion, will successfully make the ball fall into the bucket.
There is, of course, a "reset" option if your setup does not work. There is also a 'solution' button which obviously gives you the answer if you truly are stumped.
After playing with the game a bit, I'll be the first to admit that it gets extremely frustrating rather quickly. By the ninth level or so, I had no idea what the tools given to me or assorted machinery on the map would even do. Nevertheless, I saw gears, levers, even a windmill type thing which seemed to undergo uniform circular motion.
However, no matter how complicated the levels get, the key to beating each individual level is correctly visualizing what will happen to the ball as it passes each obstacle. Some tools they give you slow the ball down, probably displaying some effect of high friction. Others such as a ramp (which you can put at any angle) allow the control of how quickly the ball falls, and where it lands. On the fourth level, there are even domino blocks which cause a chain reaction through conservation of momentum.
For those of you who want to see what the game looks like but are too lazy to click the link of the actual game, I'll throw you a bone. Here's one of the first levels, where the setup is relatively easy. Notice how you can also rotate the various objects provided.
and for the rest of you, here's the game itself, along with a bunch of other "physics" related games.
I struggled for awhile to find something in my house related to nuclear physics, so I decided that really, it wasn't worth the effort. I'd have to find something else. While procrastinating, I stumbled upon this nifty game thing called 'dynamic systems.'
The game is extremely simple at first, but gets exponentially harder within the first five levels. The idea is simple: initially, a silver ball is present on the board, somewhere far, far, away from the bucket. Using the random assortment of tools provided and properties of physics, one must place various objects which, when the ball is set into motion, will successfully make the ball fall into the bucket.
There is, of course, a "reset" option if your setup does not work. There is also a 'solution' button which obviously gives you the answer if you truly are stumped.
After playing with the game a bit, I'll be the first to admit that it gets extremely frustrating rather quickly. By the ninth level or so, I had no idea what the tools given to me or assorted machinery on the map would even do. Nevertheless, I saw gears, levers, even a windmill type thing which seemed to undergo uniform circular motion.
However, no matter how complicated the levels get, the key to beating each individual level is correctly visualizing what will happen to the ball as it passes each obstacle. Some tools they give you slow the ball down, probably displaying some effect of high friction. Others such as a ramp (which you can put at any angle) allow the control of how quickly the ball falls, and where it lands. On the fourth level, there are even domino blocks which cause a chain reaction through conservation of momentum.
For those of you who want to see what the game looks like but are too lazy to click the link of the actual game, I'll throw you a bone. Here's one of the first levels, where the setup is relatively easy. Notice how you can also rotate the various objects provided.
and for the rest of you, here's the game itself, along with a bunch of other "physics" related games.
Saturday, April 3, 2010
Playing around with some purple light thing
saturday night, nothing much to do, and it was time for the physics blog. of course, the camera was in video mode by chance, but before I switched it to picture mode, my good friend Richard asked, "what's that?" Sure enough, there was a random purple line thing in the middle of the screen. And it just wouldn't go away.
Confused, I sent the following message to doc!, in hopes of enlightenment:
-----------------------------
So, I was about to use my camera to take a picture at Richard's house, but the camera was in video mode. When I hit the "record" button, I noticed a distinct purple line which cross-sectioned the view of the room, and it seemed to originate from a lamp. I moved around the camera a bit, and saw that if I rotated it enough, the purple line disappeared.
Could you point me in the right direction so I could blog about it?
thanks,
andrew
-----------------------------
and here was the response:
Interesting. It appears to be some kind of internal reflection in the lens of the camera caused by the high intensity of the light. I would guess that it as you move the camera up and down, the purple line will stay directly on the lamp. Does the line rotate as you rotate the camera? This is something like the star effects that cameras as sometimes designed to produce ... those are diffraction effects.
-----------------------------
as the video verifies, doc!'s hypothesis that the purple line would only disappear if the camera were moved side to side is correct. unfortunately, I failed to grasp very much understanding here. I googled 'star effect' and every single result seemed to be selling something.
For now, the phenomena is unresolved, both because I am stuck and because I have a lot to do tonight. I am annoyingly very confused, just like how I will be on tomorrow's physics test.
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