calculating the speed of light with cheese in a microwave

If you’ve been playing along at home, you know that I’m a teeny-tiny bit obsessed with the soon-to-be-released, 2400-page Modernist Cuisine book.  Well, my excitement skyrocketed last week when I had the rare privilege to peek at a few hundred [digital] pages of the book, guided by author, CEO and hero of geeks everywhere, Dr. Nathan Myhrvold.  I was honored by the invitation, which I can only assume was prompted by a prank phone call from the Make A Wish Foundation on my behalf.

Among the seemingly endless pages of stunning photographs, captivating history and practical instruction, the book is sprinkled with fascinating tidbits like this one.  Did you know that you can measure the speed of light using your microwave and a few slices of Kraft Singles?

From the section “Cooking in Modern Ovens”:

You can measure the speed of light by melting cheese, chocolate or even marshmallows in your microwave.  Microwave cooking leaves patterns of melting on soft, smooth surfaces that correspond to roughly half the wavelength of a microwave.  These patterns are caused by the way the microwaves crisscross in the oven chamber and either combine their energies or cancel one another out.

Here’s how to replicate the experiment at home.

  1. Cover a flat plate, platter or cardboard disc with soft cheese slices.
  2. Place the plate in the microwave.  If your microwave has a turntable, disable it, or remove the turntable platter and place the plate on an inverted ramekin to bypass the turntable motor.
  3. Heat on low power until it has melted in several spots.
  4. Measure the distance, in millimeters, between the centers of any two melt spots.  Double that number to get the wavelength. 
  5. Multiply the wavelength by the frequency, in MHz, of your microwave (listed on the back).  For example, if your microwave is 2.45GHz (typical), you’d multiply by 2,450,000.  [We multiply by MHz instead of GHz to fudge in a factor of 1000, which is the conversion from millimeters to meters.]
  6. Compare your value to the generally accepted value of 299,792,458 meters per second

The value I calculated was 306,019,200, which is is only off from the actual value by 2%.  Not bad for fake cheese! 

Between now and the release of the book in March, I’ll be highlighting a few more geeky food tricks from the book.  In the meantime, you can find more information at http://modernistcuisine.com/.  If you’re ready to pull the trigger, the book is available for pre-order on Amazon.com.

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Do try this at home, but don’t burn your house down!

This turned out to be one of the more dangerous machines I’ve ever built.  The goal was to make a cotton candy machine out of parts I had lying around.  The finished product was an aggressive, 1/2 horsepower, 4000°F beast of a machine that lasted long enough to prove itself before dying of awesomeness. 

If you want to build a cotton candy machine at home, all you need is:

  • A tin can, like a tuna or dog food can
  • A drill with a very small drill bit
  • A motor (ex, your drill, an old CD player, a blender)
  • A heat source, such as a propane torch, a lighter, or the coils from an old toaster
  • A bucket to catch the cotton candy, or alternately a sheet of paper to wrap around the assembly
  • Sugar

Follow the steps in the video to see just how easy this machine is to build.  Oh, and don’t forget… safety first.  My favorite part of this project was setting up a blast shield in front of the camera before we turned on the machine.

cotton candy build
Special thanks to Victor (@sphing) for filming!

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If making alcohol had been this easy during prohibition, homemade hooch would have been everywhere.  A few weeks ago, I began playing with a product called Spike Your Juice, which was advertised as a way to turn juice into alcohol in 48 hours.  It works like this: pick a juice with at least 20g of sugar per serving, add a packet of their specially-designed yeast, plug the bottle with an airlock, and wait 48 hours.  Just like the fermentation process used in winemaking, the juice’s natural sugar is converted into ethanol, with a byproduct of carbon dioxide.  The result is an alcoholic drink with a champagne-like effervescent fizz.

I bought a box of these magic bacteria and started experimenting.  The instructions recommend using filtered juices that don’t require refrigeration and aren’t artificially sweetened. But, I’m bad at following instructions, and I don’t trust a juice that doesn’t require refrigeration.  I grabbed a bottle of Pink Lemonade, Mango, Blackberry and Sweet Tea from Trader Joe’s.  The pink lemonade worked well – after 48 hours, it was quite fizzy, though I couldn’t really taste the alcohol.  The Sweet Tea fizzed a bit, but also didn’t taste “spiked” – it just tasted awful.  The Mango juice (which wasn’t fully filtered) formed big solid clumps during fermentation.  I’m not sure why, exactly, but they were gross so I filtered them out with cheesecloth before drinking.  Again, some fizz, no buzz. 

The Blackberry juice was the winner by far.  It also developed some solids (even though it was very clear juice to begin with), and you’d never mistake it for wine, but it was delicious.  Think blackberry Lambic, but with an adjusted price of $1.75 per bottle (64oz of juice at $3, $1.50 per packet of yeast, 25oz in a wine bottle).  This is something I’d make again, and certainly something I’d serve to dinner guests or corruptible children. 

The instructions state that you can allow the fermentation to continue longer than 48 hours to achieve up to 14% ABV.  It also recommends using Welch’s or Ocean Spray – I guess we’ll have to agree to disagree there.  To me, the best part of this product is that you’re free to choose great starting ingredients, like a locally-produced cider, or raspberry juice from plants in your back yard.  But for the fun of quick, easy DIY booze, I’ll raise my glass to this product!

Spike Your Juice – $9.99 (or $20 for a 2-pack on Amazon)

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