so, good luck to you all. or, congrats on surviving AP physics. depending on when you're reading this.
doc! and to all readers, there's been good times and bad times. thanks for a great year!
in favor of studying, my last "required" blog will be cut short, i think. i got a few tips on how to do this quickly and effectively.
--------------------------------------------------------------------
So. I was at my desk. Wondering what to write about. And then I remembered something. It was a time when I went through a revolving door. There's me going in like a boss. Force perpendicular to the radius to maximize torque. Like a boss. since torque = r F sin theta, i remembered that sin theta is 1 at 90 degrees.
Then there's Matt Lum. Show him how its done Grozen.
I do so bad on tests man, I remember this time I got like a 70 or something and posted about it on my blog. I might get a C this quarter. I saw kelly and jrad today. they were like, within 800 meters of each other. yup, thats scandalous
Monday, May 10, 2010
Monday, May 3, 2010
things that shine with the colors of a rainbow
Today, I noticed in the shower at some point, that a good number of the bubbles I made were clear and transparent but still shined with colors of a rainbow. It occurred to me that I had no idea why bubbles shine with the colors of a rainbow.
I found out the reason why bubbles shine with colors of the rainbow: the variety of colors was the result of thin-film interference.
When white light hits an object, some of it is reflected back. Thus causing the object to shine with the colors of a rainbow. Consider the following scenario for a bubble which shines with the colors of a rainbow:
When light bounces off the bubble, it undergoes a 180 degree phase change as it moves to a media with a higher index of refraction, a crucial first step in making it shine with the colors of a rainbow.
The rest of the light passes through the bubble and consequently reflects back without phase change at the second interface between air and bubble. This causes the white light waves to travel different lengths toward the same point.
Different things will happen when the light waves coincide. If the waves differ by 180 degrees, they will both shine with the colors of the rainbow. No, not really--no light will appear. If the waves coincide, light appears. Different colors within the visible light spectrum have different wavelengths and are affected differently while passing through a bubble. Wavelength and index of refraction are directly related; hence, when passing through the bubble, only certain colors will appear, thus making the bubble shine with colors of a rainbow.
PS: while looking at bubbles which shine like colors of a rainbow, i did not really fancy the idea of getting my camera wet. so i used someone else's which had a similar effect.
PPS:
@ david: if you don't look at it that way, it's not obscene. jesus.
I found out the reason why bubbles shine with colors of the rainbow: the variety of colors was the result of thin-film interference.
When white light hits an object, some of it is reflected back. Thus causing the object to shine with the colors of a rainbow. Consider the following scenario for a bubble which shines with the colors of a rainbow:
When light bounces off the bubble, it undergoes a 180 degree phase change as it moves to a media with a higher index of refraction, a crucial first step in making it shine with the colors of a rainbow.
The rest of the light passes through the bubble and consequently reflects back without phase change at the second interface between air and bubble. This causes the white light waves to travel different lengths toward the same point.
Different things will happen when the light waves coincide. If the waves differ by 180 degrees, they will both shine with the colors of the rainbow. No, not really--no light will appear. If the waves coincide, light appears. Different colors within the visible light spectrum have different wavelengths and are affected differently while passing through a bubble. Wavelength and index of refraction are directly related; hence, when passing through the bubble, only certain colors will appear, thus making the bubble shine with colors of a rainbow.
PS: while looking at bubbles which shine like colors of a rainbow, i did not really fancy the idea of getting my camera wet. so i used someone else's which had a similar effect.
PPS:
@ david: if you don't look at it that way, it's not obscene. jesus.
Sunday, April 25, 2010
Life Lessons #2: How to Escape from Quicksand
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
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
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.
Monday, March 15, 2010
Contacts
Busy weekend, busy day, busy sunday night.. not much else needs to be said!
so here's a quickie:
From my time here at Iolani, I'd say that I've seen more people wearing glasses than anywhere else in my life. I can't really tell you why we all have bad eyesight, but I do too. But me, I wear contacts. Contact lenses. Something we've been studying about in physics.
Since you unsophisticated people wear glasses, today's lesson is about how to properly put on a contact. While each pair of contact lenses is lightweight, transparent, and looks the same oriented forward or backward, believe it or not there's a very specific way to put them on. First, hands gotta be clean and dry, but moist. Contacts must be inserted, concave side up. Otherwise, as us sophisticated guys know, very painful irritation occurs and vision is severely impaired.
The issue is, the irritation only kicks in moments after you put in the contacts. And your vision is always impaired when you put in the lens, but if done correctly, should cease after a minute. If the lens are inserted convex side up, vision is strangely enough, impaired forever. To the point where one can see better without having them on. But I digress....
So to give you an idea of what life was like, when I confused convex side with concave side:
I woke up, but didn't really wake up, and could barely pry my eyes open to get the contacts in..
I was late, and noticed that my eyes, still tired and closed felt like they were swelling on the way to school. I opened my eyes and realized I couldn't see a thing. Class was pretty fun, having to tap the person next to me to figure out what my teachers were writing on the board. And then Mr. Park put me on the spot, and I didn't even know what the question was...
If you mix up the sign, it's almost as fatal as forgetting a negative sign on object or image distance on a quiz. Almost.
so here's a quickie:
From my time here at Iolani, I'd say that I've seen more people wearing glasses than anywhere else in my life. I can't really tell you why we all have bad eyesight, but I do too. But me, I wear contacts. Contact lenses. Something we've been studying about in physics.
Since you unsophisticated people wear glasses, today's lesson is about how to properly put on a contact. While each pair of contact lenses is lightweight, transparent, and looks the same oriented forward or backward, believe it or not there's a very specific way to put them on. First, hands gotta be clean and dry, but moist. Contacts must be inserted, concave side up. Otherwise, as us sophisticated guys know, very painful irritation occurs and vision is severely impaired.
The issue is, the irritation only kicks in moments after you put in the contacts. And your vision is always impaired when you put in the lens, but if done correctly, should cease after a minute. If the lens are inserted convex side up, vision is strangely enough, impaired forever. To the point where one can see better without having them on. But I digress....
So to give you an idea of what life was like, when I confused convex side with concave side:
I woke up, but didn't really wake up, and could barely pry my eyes open to get the contacts in..
I was late, and noticed that my eyes, still tired and closed felt like they were swelling on the way to school. I opened my eyes and realized I couldn't see a thing. Class was pretty fun, having to tap the person next to me to figure out what my teachers were writing on the board. And then Mr. Park put me on the spot, and I didn't even know what the question was...
If you mix up the sign, it's almost as fatal as forgetting a negative sign on object or image distance on a quiz. Almost.
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