Tag Archives: cool

Home Experiment: Deriving the Gravitational Constant

Deriving the Gravitational Constant by Joe Marshall

In the summer of 1985 I was at home convalescing and being bored. It occurred to me one day that if Cavendish could determine the gravitational constant back in 1798, I ought to be able to do something similar
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Cavendish cast a pair of 1.61 pound lead weights. I found a couple of 2-pound lead cylinders my dad had lying around. I used duct tape to attach them to a 3-foot wooden dowel. Cavendish used a wire to suspend the balance, I used nylon monofilament. To determine the torsion of the fiber, you wait until the balance stops moving (a day or two) and then you slightly perturb it. The balance will slowly oscillate back and forth. The restoring force is calculated from the period of oscillation. Cavendish had a 7-minute period. My balance had a 40 minute period (nylon is nowhere near as stiff as wire).

Cavendish used a pair of 350 pound lead balls to attract the ends of the balance from about 9 inches away. I put a couple of 8 pound jugs of water about an inch away. The next trick was to measure the rotation of the balance. Cavendish had a small telescope to read the Vernier scale on the balance. I used some modern technology. I borrowed a laser from Tom Knight (Thanks again!), and bounced it off a mirror that I mounted on the middle of the balance. This made a small red dot on the wall about 20 feet away. (I was hoping this would be enough to measure the displacement, but I was considering an interferometer if necessary.)

To my surprise, it all worked. After carefully putting the jugs of water in place, the dot on the wall started to visibly move. Within a few minutes, it had moved an inch or two. I carefully removed the jugs of water and sure enough, the dot on the wall drifted back to its starting position.

Very cool example of a home physics experiment.

Bacteria Communicate Using a Chemical Language

Each person has about 1 trillion human cells and about 10 trillion bacterial cells. In the webcast Bonnie Bassler, Department of Molecular Biology at Princeton University, discusses the chemical language that lets bacteria coordinate defense and mount attacks (quorum sensing). The find has stunning implications for medicine, industry — and our understanding of ourselves.

Bacteria do all sorts of amazing things for us: educating your immune system to keep bad microbes out, they digest our food, they make our vitamins…

Build Your Own Tabletop Interactive Multi-touch Computer

This is a fantastic Do-It_Yourself (DIY) engineering story. Very interesting, definitely go read the whole article: Build Your Own Multitouch Surface Computer

First, some acknowledgments are in order. Virtually all the techniques used to create this table were discovered at the Natural User Interface Group website, which serves as a sort of repository for information in the multitouch hobbyist community.
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In order for our setup to work, we needed a camera that senses infrared light, but not visible light. It sounds expensive, but you’d be surprised. In this section, we’ll show you how we created an IR camera with excellent resolution and frame-rate for only $35—the price of one PlayStation 3 Eye camera. “But that’s not an IR camera,” you say? We’ll show you how to fix that.

As it turns out, most cameras are able to sense infrared light. If you want to see first-hand proof that this is the case, try this simple experiment: First, find a cheap digital camera. Most cell phone cameras are perfect for this. Next, point it at the front of your TV’s remote control. Then, while watching the camera’s display, press the buttons on the remote. You’ll see a bluish-white light that is invisible to the naked eye. That’s the infrared light used by the remote to control the TV.
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Like the computer, the projector we used for the build was something we scavenged up. The major concern for a projector to use in this kind of system is throw distance—the ratio between projection distance and image size. Short-throw projectors, which are sold by all the major projector brands, work the best for this kind of project, because they can be set up at the bottom of the cabinet and aimed directly at the surface. Unfortunately, they also tend to be more expensive.

Ever thrifty, we went with a projector we could use for free: an older home-theater projector borrowed from a friend. Because of the longer throw distance on this model, we had to mount the projector near the top of the cabinet, facing down, and use a mirror to reflect the image up onto the screen. For this we ordered a front-side mirror (a mirror with the reflective surface on the front of the glass, rather than behind it) to eliminate any potential “ghosting” problems, caused by dual reflections from the front and back of the glass in an ordinary mirror.

What is on the Other Side of Earth?

Do you ever wonder what is on the exact opposite side of Earth? This website uses Google Maps to let you see: Antipodes Map. It also makes clear how much of the earth is covered in oceans. The entire continental USA is opposite ocean. Hawaii is opposite Botswana and Namibia. Hong Kong is opposite Argentina. Singapore opposite Ecuador. India, Ireland, Turkey, France and Egypt are among the many countries that opposite oceans. Madrid is opposite New Zealand.

Google Server Hardware Design

Ben Jai, Google Server Platform Architect, discusses the Google server hardware design. Google has designed their own servers since the beginning and shared details this week on that design. As we have written previously Google has focused a great deal on improving power efficiency.

Google uncloaks once-secret server

Google’s big surprise: each server has its own 12-volt battery to supply power if there’s a problem with the main source of electricity. The company also revealed for the first time that since 2005, its data centers have been composed of standard shipping containers–each with 1,160 servers and a power consumption that can reach 250 kilowatts.
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Efficiency is another financial factor. Large UPSs can reach 92 to 95 percent efficiency, meaning that a large amount of power is squandered. The server-mounted batteries do better, Jai said: “We were able to measure our actual usage to greater than 99.9 percent efficiency.”

Robot Independently Applies the Scientific Method

Robot achieves scientific first by Clive Cookson

A laboratory robot called Adam has been hailed as the first machine in history to have discovered new scientific knowledge independently of its human creators. Adam formed a hypothesis on the genetics of bakers’ yeast and carried out experiments to test its predictions, without intervention from its makers at Aberystwyth University.

The result was a series of “simple but useful” discoveries, confirmed by human scientists, about the gene coding for yeast enzymes. The research is published in the journal Science.
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Adam is the result of a five-year collaboration between computer scientists and biologists at Aberystwyth and Cambridge universities.

The researchers endowed Adam with a huge database of yeast biology, automated hardware to carry out experiments, supplies of yeast cells and lab chemicals, and powerful artificial intelligence software. Although they did not intervene directly in Adam’s experiments, they did stand by to fix technical glitches, add chemicals and remove waste.
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“Adam is a prototype,” says Prof King. “Eve is better designed and more elegant.” In the new experiments, Adam and Eve will work together to devise and carry out tests on thousands of chemical compounds to discover antimalarial drugs.

Very cool.

Robot with Biological Brain

The Living Robot by Joe Kloc

Life for Warwick’s robot began when his team at the University of Reading spread rat neurons onto an array of electrodes. After about 20 minutes, the neurons began to form connections with one another. “It’s an innate response of the neurons,” says Warwick, “they try to link up and start communicating.”

For the next week the team fed the developing brain a liquid containing nutrients and minerals. And once the neurons established a network sufficiently capable of responding to electrical inputs from the electrode array, they connected the newly formed brain to a simple robot body consisting of two wheels and a sonar sensor.
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At first, the young robot spent a lot of time crashing into things. But after a few weeks of practice, its performance began to improve as the connections between the active neurons in its brain strengthened. “This is a specific type of learning, called Hebbian learning,” says Warwick, “where, by doing something habitually, you get better at doing it.”
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“It’s fun just looking at it as a robot life form, but I think it may also contribute to a better understanding of how our brain works,” he says. Studying the ways in which his robot learns and stores memories in its brain may provide new insights into neurological disorders like Alzheimer’s disease.

Google Summer of Code 2009

Google Summer of Code is a global program that offers student developers stipends to write code for various open source software projects. Google funds the program with $4,500 for each student (and pays the mentor organization $500). Google works with several open source, free software, and technology-related groups to identify and fund projects over a three month period.

Since its inception in 2005, the program has provided opportunities for nearly 2500 students, from nearly 100 countries. Through Google Summer of Code, accepted student applicants are paired with a mentor or mentors from the participating projects, thus gaining exposure to real-world software development scenarios and the opportunity for employment in areas related to their academic pursuits. In turn, the participating projects are able to more easily identify and bring in new developers. Best of all, more source code is created and released for the use and benefit of all.

Google funded approximately 400 student projects in 2005, 600 in 2006, 900 in 2007 and 1125 in 2008 and will be funding approximately 1,000 student projects in 2009.

Applying for the program is only allowed from March 23rd through April 3rd. Still a short period of time but in previous years they have only taken them for one week. Organizations hosting students include: Creative Commons, MySQL, Debian, The Electronic Frontier Foundation/The Tor Project, haskell.org, Grameen Foundation USA, National Center for Supercomputing Applications, Ruby on Rails, Wikimedia Foundation and WordPress. See the full list of organizations and link to descriptions of the projects each organization offers.

See the externs.com internship directory (another curiouscat.com ltd. site) for more opportunities including those in science and engineering.

Friday Cat Fun #14: Scuba Cat

The video was removed 🙁

Scuba cat with pal – scuba dog. What does scuba stand for? Self-Contained Underwater Breathing Apparatus.

Home Engineering: Gaping Hole Costume

photo of gaping hole Halloween costume by Evan Booth, 2006

This great Halloween costume by Evan Booth shows what a bit of imagination and engineering can do. A projection screen over his stomach displays a live video image of a camera on his back giving the illusion of a gaping hole. Photos via flickr. Very cool.