Tag Archives: science

Weekend Projects with Bre Pettis: Make a Joule Thief

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Weekend Projects Podcast!
In this week’s Weekend Projects video podcast, Make Magazine’s Bre Pettis and I show you how to make a Joule Thief. The PDF file that goes with the podcast is here (450 kB PDF file).

So whatsa Joule Thief? It’s a little wisp of a circuit that allows you to drive a blue or white LED from a low voltage. Normally, if you want to light up a blue or white LED you need to provide it with 3 – 3.5 V, like from a 3 V lithium coin cell. But a 1.5 V battery like a AA cell simply will not work. But using the Joule Thief, it works like a charm. Not only does it work with a brand new battery, but it works until the battery is nearly dead– down to 0.3 V. That’s well below the point where your other toys will tell you the battery is dead, so it can steal every last joule of energy from the battery (hence the name). To learn how to make one, watch the video, which is available in a variety of formats.

The original site where we learned about the Joule thief shows you how to make a miniature version of this circuit, such that you can fit it in a tiny flashlight. However, in the video we show you how to make it big, large enough (1) to make with clumsy hands and (2) that you can see what we’re doing.

After the jump, some detailed photos of how the coil is wound in case you need more detail than in the video.

Continue reading Weekend Projects with Bre Pettis: Make a Joule Thief →

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Make a physics education video and win the Phylm Prize!

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“Phylm,” pronounced as “film,” is a portmanteau built out of the words “physics” and “film.” It’s also the name given to a new award, The Phylm Prize, aimed at spurring interest in physics and the educational use of new media. Translation: it’s a YouTube contest for physics geeks!

We’ve been invited to sit on the panel of judges for the contest, and so we’ll be looking forward to seeing the submissions. Videos up to two and a half minutes long featuring physics will be judged on clarity, accuracy, and creativity. This year’s winner will receive a check for $100 (US) to be dispersed in June 2007.

You can watch the video announcement at YouTube or (embedded) here:

We are guessing that many of you, our fine readers, already have an interest in physics and/or new media, so get started already! Let’s see your submissions! And don’t let the word “educational” intimidate you– educational propaganda is a highly appropriate diversion for evil mad scientists! (Besides, you could probably use the cash for your world domination scheme.)

Here’s some info from the rules on what kinds of things the clips can contain:

  • A critique/analysis of the physics presented in a fictional work. For example,
    could the bus in Speed have made “the jump,” or how strong would Spider-Man
    have to be to throw a car that far?
  • An analysis of physics as revealed by the examination of a real-world video clip.
    For example, what forces does a gymnast experience during his routine?
  • An explanation/presentation of some physics concept or theory. For example, what is the conservation of energy?

Submissions are due by 12:00 am (GMT) May 1, 2007. We’ll be waiting.

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Quips, Quirks and Quarks

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In the mid 1990’s, many things were considered socially acceptable that no longer are. Among these are jokes about Lorena Bobbitt and/or Tonya Harding, anything having to do with Mighty Morphin Power Rangers, and internet humor mailing lists. I am guilty of the latter: From 1994 to 1997 I ran a daily humor mailing list called Quips, Quirks & Quarks, or more commonly QQQ.

The archives of QQQ are on one of my “old” web pages, where you can peruse this vast nearly-organized trove of treasure and trash. The quality of the material varies greatly, and the presentation is an excellent example of web 1.0 (or maybe 0.8 beta) design ethic.

Here are some samples from the collection:

  • From the collection of Quips (the jokes):
    • My wife is very immature– Just tell me if this doesn’t sound immature.
      She’ll barge right into the bathroom when I’m in the tub and sink all
      of my boats!
    • “Doctor, is it really true that eating carrots improves ones eyesight?”
      “Of course. Have you ever seen rabbits wearing glasses?”
  • From the collection of Quirks (the weird):
    • Hi-Tech Haiku:
      the sand remembers
      once there was beach and sunshine
      but chip is warm too
    • roses are red
      violets are blue
      some poems rhyme
      and some don’t

 

  • From the collection of Quarks (the nerdy):
    • Q: What do you do with 56 dead protons?
      A: Barium.
    • Q: Why won’t feminists use Unix?
      A: There aren’t any woman pages.

 

  • From the collection of One liners:
    • Asking if computers can think is like asking if submarines can swim.
    • Proofread carefully to see if you any words out.

 

 

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Three magnetohydrodynamic propulsion projects

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Today we’re publishing three articles on magnetohydrodynamic (MHD) propulsion, a means of propelling a ship without moving parts like paddlewheels or propellers. Instead, MHD relies on passing electrical currents through the water, effectively turning the water itself into part of an electric motor, where the only thing that moves is the water.

Here’s a quick guide to the articles:

  • First Demonstrate magnetohydrodynamic propulsion in one minute. You’ll need a magnet, a battery, two wires, water, and salt and pepper.
  • Next, Build a simple boat that propels itself with a magnetohydrodynamic drive.
  • Finally Get serious, and start hacking magnetohydrodynamic propulsion systems into RC boats.

PS: Happy International Talk Like a Pirate Day. Arr.

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MHD III: Hacking an RC Boat to use Magnetohydrodynamic Propulsion

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Mod a cheap radio control boat into an RC magnetohydrodynamic vehicle.

This design serves as proof of principle for modding an RC vehicle to run on MHD. Rather than being a performance design, it travels at an astonishing speed of several feet per minute since it uses essentially the same design as our foam-tray MHD boat.

Read on to find out how we made the conversion, what worked and what didn’t, and how we plan to get some speed in the next revision.
Continue reading MHD III: Hacking an RC Boat to use Magnetohydrodynamic Propulsion →

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MHD II: Make a magnetohydrodynamic propulsion boat

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After trying out our simple demonstration of magnetohydrodynamic (MHD) propulsion, you might want to make something a little more “practical.” Here’s how to build a simple little boat that moves through salt water (at a snail’s pace) via MHD propulsion.

The craft is not designed for performance; it’s designed to demonstrate a functional MHD craft made with inexpensive, easily available materials. While it may move slowly, hey, it moves, and you can make it in about five minutes.
Continue reading MHD II: Make a magnetohydrodynamic propulsion boat →

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MHD I: Demonstrate Magnetohydrodynamic Propulsion in a Minute

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Rember the silent caterpillar drive from the movie The Hunt for Red October? The caterpillar drive was a fictional magnetohydrodynamic propulsion system. Magnetohydrodynamic (MHD) propulsion is a means of using electrical current, instead of a noisy propeller, to push a ship through the water.
Surprisingly enough, a working example of this futuristic drive system is quite easy to build. Assuming that you’ve got the materials handy, you can build one in about a minute. You’ll need a strong magnet, two pieces of thick copper wire, a little dish of warm water, salt and pepper, and a regular battery.
Continue reading MHD I: Demonstrate Magnetohydrodynamic Propulsion in a Minute →

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Super-Easy Supermagnet Compass

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When I was a kid, I read in a science book about how to make a directional compass. You magnetize a sewing needle and balance it on a cork floating in a bowl of water. Even today, this is the standard story. For example, How Stuff Works still says that this is how to make a compass. (There are a lot of other examples, too.) It turns out that it’s a whole lot easier than that. All you need is a really good magnet.
Continue reading Super-Easy Supermagnet Compass →

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The mercury ion optical clock

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From 2002-2005 I worked in the NIST Time and Frequency division on a next-generation atomic clock.

The clock is based on a single trapped mercury atom. The most significant result of my work on the clock was a dramatic improvement in its precision, and the report on this progress was finally published this week.

The NIST Press Release compares the accuracy of the mercury clock to the NIST-F1 cesium fountain standard: “The current version of NIST-F1—if it were operated continuously—would neither gain nor lose a second in about 70 million years. The latest version of the mercury clock would neither gain nor lose a second in about 400 million years.”

Read an article from Science News about the paper, or one from Seed Magazine.
Continue reading The mercury ion optical clock →

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