Anti-Gravity Mirror - It's all done with mirrors!

Anti-Gravity Mirror

 

It's all done with mirrors.

A reflection of your right side can appear to be your left side. With this Snack, you can appear to perform many gravity-defying stunts. 

 

• A large, flat, plastic mirror, 2 x 3 feet (60 x 90 cm) or larger
  It is important to get a good, flat mirror, since distortions will ruin the effect. Plastic mirrors are expensive, but glass mirrors can be dangerous. Look in your local yellow pages for a nearby plastics store.
• A length of 2 x 4 inch wood and a router tool, or ring stands and clamps,
  This makes a stand to hold the mirror upright.
• Optional: A sturdy table on which you can stand.
• A partner. Adult help.

 

(with stand:15 minutes or less: without: 5 minutes or less)
You can make a stand for the mirror from a length of 2 x 4 inch wood. Use a router to cut a groove that is just wide enough to slip the mirror into. To help stabilize the mirror, you can nail some scrap wood to the ends of the board. You can also hold the mirror in a vertical position using ring stands and clamps, or just with your hands. An assistant might be of help here.

(15 minutes or more)
Stand the mirror on the floor or on a sturdy table. Put one leg on each side of the mirror. Shift your weight to the foot behind the mirror. Lift your other leg and move it repeatedly toward and away from the mirror. To an observer, you'll appear to be flying. If you use this Snack as a demonstration, you can make the effect more dramatic by covering the mirror with a cloth, climbing onto the table, straddling the mirror, and then dropping the cloth as you "take off."

A person standing with the edge of a large mirror bisecting his or her body will appear whole to a person who's watching. To the observer, the mirror image of the left half of a person looks exactly like the real right half. Or if the person is standing on the opposite end of the mirror, the right half looks like the real left half. The person looks whole because the human body is symmetrical. The observer's brain is tricked into believing that an image of your right side is really your left side. So just straddle the mirror, raise one leg, and you'll fly!

Try this out in department stores that have full-length mirrors available. If your school has a dance room with a mirrored wall and a doorway cut into it, you may be able to use it. With these full mirrors, stand at the edge of the doorway so that just half of your body is being reflected. This will be an even more convincing flight.

The cars that floated across the desert in the movie Star Wars each had a full-length mirror attached along their lower edge, hiding the wheels. A camera pointed at a car saw a view of reflected sand and shadow in the mirror. That is how the cars appeared to float above the sand.

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A flash of light prints a lingering image in your eye.

 

Afterimage

A flash of light prints a lingering image in your eye.

After looking at something bright--such as a lamp or a camera's flash--you may continue to see an image of that object when you look away. This lingering visual impression is called an afterimage. 

• A flashlight
• White paper
• Opaque black tape (such as electrical tape).

(15 minutes or less)
Tape a piece of white paper over a flashlight lens. Cover most of this paper with strips of opaque tape. In the center of the lens, leave an area uncovered, so that the light can shine through the paper. This area should be a square, a triangle, or some other simple, recognizable shape.

(15 minutes or more)
In a darkened room, turn on the flashlight, hold it at arm's length, and shine it into your eyes. Stare at one point of the brightly lit shape for about 30 seconds. Then stare at a blank wall and blink a few times. Notice the shape and color of the image you see. Try again--first focusing on the palm of your hand, and then focusing on a wall some distance from you. Compare the size of the image you see in your hand to the image you see on the wall. Close your left eye and stare at the bright image with your right eye. Then close your right eye and look at the white wall with your left eye. You will not see an afterimage.

You see because light enters your eyes and produces chemical changes in the retina, the light-sensitive lining at the back of your eyes. Prolonged stimulation by a bright image (here, the light source) desensitizes part of the retina. When you look at the white wall, light reflecting from the wall shines onto your retina. The area of the retina that was desensitized by the bright image does not respond as well to this new light input as the rest of the retina. This area appears as a negative afterimage, a dark area that matches the original shape. The afterimage may remain for 30 seconds or longer.

The apparent size of the afterimage depends not only on the size of the image on your retina, but also on how far away you perceive the image to be. When you look at your hand, you see the negative afterimage on your hand. Because your hand is near you, you see the image as relatively small--no bigger than your hand. When you look at a distant wall, you see the negative afterimage on the wall. But it is not the same size as the afterimage you saw on your hand. You see the afterimage on the wall as much bigger--large enough to cover a considerable area of the wall. The afterimage is not actually on either surface, but on your retina. The actual afterimage does not change size; only your interpretation of its size changes.

This helps explain a common illusion that you may have noticed. The full moon often appears larger when it is on the horizon than when it is overhead. The disk of the moon is the exact same size in both cases, and its image on your retina is also the same size. So why does the moon look bigger in one position than in the other? One explanation suggests that you perceive the horizon as farther away than the sky overhead. This perception might lead you to see the moon as a large disk when it is near the horizon (just as you saw the afterimage as larger when you thought it was on the distant wall), and as a smaller disk when it is overhead (just like the smaller afterimage in the palm of your hand).

Negative afterimages do not transfer from one eye to the other. This indicates that they are produced on the retina, and not in the visual cortex of the brain where the signals would have been fused together.

For up to 30 minutes after you walk into a dark room, your eyes are adapting. At the end of this time, your eyes may be up to 10,000 times more sensitive to light than they were when you entered the room. We call this improved ability to see night vision. It is caused by the chemical rhodopsin, in the rods of your retina. Rhodopsin, popularly called visual purple, is a lightsensitive chemical composed of vitamin A and the protein opsin.

You can use the increased presence of rhodopsin to take "afterimage photographs" of the world. Here's how:

Cover your eyes to allow them to adapt to the dark Be careful that you do not press on your eyeballs. It will take at least 10 minutes to store up enough visual purple to take a "snapshot." When enough time has elapsed, uncover your eyes. Open your eyes and look at a well-lit scene for half a second (just long enough to focus on the scene), then close and cover your eyes again. You should see a detailed picture of the scene in purple and black. After a while, the image will reverse to black and purple. You may take several "snapshots" after each 10-minute adaptation period.

For a more complete desciption of this experiment, see Paul Hewitt's Conceptual Physics Lab Manual (HarperCollins College Publishers, New York, 1993).

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Geek deals: $180 discount Dell XPS 12 convertible, 50-inch plasma

When it comes to laptops, there is one major thing that catches my eyes: the screen. Not only do I have a preference towards high resolution (as we’ve covered many a time in these deals), but the quality of the screen is paramount as well.

When you can get an ultraportable laptop with a top notch screen and great performance, it is nearly an event worth celebrating. When the same machine is available in an innovative, convertible chassis, that’s pretty sweet. Toss in some rare discounts and we’ve got the makings of a hot deal.

 

Dell’s XPS 12 is definitely one of the more unique laptops available today. The 12.5-inch display serves up an impressive 1920×1080 pixels and does it on an IPS multi-touch LCD panel. Not only is it super crisp and gorgeous high resolution, but the wide viewing angles, rich colors, and of course touch capability combine to make for one killer screen.

Then consider the XPS 12′s unique chassis: the screen rotates within the display frame itself, allowing you to use it as either a traditional laptop or slate tablet. We’ve seen similar tricks before on other tablets, but none that achieved it quite like this and the reviews look good.

Right now you can get a bonus $80 coupon on any of the XPS 12 models. Combining this with $100 instant savings on the base model with Core i5, 4GB of RAM, and 128GB SSD nets you the lowest-ever price on an XPS 12 — $1019.99.

If you can front a little more coin, you can snag an upgraded model with 8GB RAM and 256GB SSD for $1419.99 after coupon, plus a $300 Dell e-gift card. This gift card is good for anything sold by Dell.com, so presuming you want to snag some new electronics anyway, this results in a net out of pocket cost of just $1119.99 for a well spec’d premium machine.

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Thinner MacBook Pro using a Haswell processor expected at WWDC

On June 10 Apple kicks off its 4-day Worldwide Developers Conference in San Francisco, better known as WWDC. Last year’s conference saw a new MacBook Pro unveiled complete with a Retina Display and a resolution of 2560 x 1600. And this year the focus is yet again expected to be on the MacBook Pro and Apple’s thinner and lighter laptop the MacBook Air.
Of course, Apple isn’t saying anything until WWDC begins, but that doesn’t stop analysts taking educated guesses as to what we can expect to see. This year, Intel’s Haswell processors are expected to allow Apple to make a few changes to their laptop line up. More specifically, it’s expected the Pro models will get even thinner.

Currently, both the MacBook Pro and Air use Intel’s Ivy Bridge processors. Haswell improves upon Ivy Bridge in a number of ways, but most significantly for Apple, reduces power consumption and adds an advanced power saving system. That means less heat production and the same battery life from a smaller battery.

If Apple embraces Haswell early, which it is expected to do, we could see a new MacBook Pro unveiled that’s even thinner than the current 0.95-inch 2012 version. Alternatively, we could see the thickness stay the same, but the battery life extended beyond the existing 7 hours Apple quotes.

KGI securities analyst Ming-Chi Kuo believes Apple will opt for a thinner MacBook Pro. The FaceTime HD camera is also expected to improve from the existing 720p part to a 1080p-capable solution. As for the MacBook Air, alongside a similar move to Haswell processors, it’s also expected that dual built-in microphones will be added for improved voice quality.

Such improvements are just speculation, but I’m sure many would argue the MacBook Pro is already thin enough and improved battery life is more desirable. Apple shipping a new Pro that looks the same as the existing model, but achieves 10 hours of battery life surely wouldn’t lose it any fans. A similar battery life improvement for the MacBook Air would also no doubt be welcomed.

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Asus Brings Intel Haswell Processors To Laptops & Desktops

Intel recently announced their 4th-Generation Core Processor codenamed Haswell and PC makers are already making news about including them in their upcoming systems. Among them Asus has announced their next desktops and all-in-ones which would be housing the Haswell chips right before Computex trade show, which is to be held at Taipei. The other companies include Cyberpower and MicroCenter. At Computex, other PC makers are expected to display their new PCs including the major manufacturers like Dell, Acer and others.

The Haswell chips add about 10 to 15 percent increase in their performance compared to the previous 3rd-Generation Core Processors codenamed Ivy Bridge. These chips are said to have lesser power consumption and lower heat generation and a considerable increase in the efficiency in battery life in laptops also.

Intel has announced only 4th-Generation Core i5 and i7 processors, with several others to be announced later at Computex. Among the two, the latter is the most powerful. Gaming desktops with Haswell processors, along with graphic cards would be able to handle any high demanding games out there. The Haswell has better speed and power efficiency over the previous Ivy Bridge processors which is equal to the same jump it had from the Sandy Bridge processors. With Haswell, consumers could have a mean desktop computer in their homes.

Haswell processors are expected to be rolled into the upcoming desktops and laptops soon, and will eventually make their way into ultrabooks. It didn't take long for the 4th-Generation Processors to be released after the previous Ivy Bridge Processors which came out just last year. Intel has always dominated the desktop and laptop processor market with AMD fighting with their processors and APUs. With the fabrication of these processors going down and the efficiency going sky high, a lot is expected for the future architecture of processors fron Intel. People might have always thought why Intel hasn't entered the mobile processor domain where Samsung and Qualcomm are leading the race, but who knows, Intel may have something up its sleeve, hidden from us.

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