We’re six days into the DonorsChoose challenge, and at the time of this writing, ten people have contributed just over $1,700 to the Uncertain Principles challenge entry. That’s an impressive average, and I thank you all for your generosity.

I also offered a number of incentives, and Lauren Uroff is claiming one:

I’d like to take you up on your offer to answer questions. The first question I’d like help with is telling me how to tell my teenager about wave-particle duality, the classic experiments that show light is both a particle and a wave, and why he should care.

As It happens, I have just the thing for this…


If you click on the image, you’ll get taken to a PDF of the final version of Chapter 1 of How to Teach Physics to Your Dog, “Which Way? Both Ways: Particle-Wave Duality.” This is laid out just the way it will be in the final book (though the book won’t have the big watermark behind it), when it gets released in December. It goes through the history of particle-wave duality, including the classic experiments showing the particle nature of light and the wave nature of matter. And it’s got a cute dog…

I hope that helps explain things to your teenager, Lauren, and I’ll post something about your second question a little later. And anybody else who wants a question answered in public, a donation of $20 to my Challenge page gets you both an answer to a question, and a chance at an advance copy of How to Teach Physics to Your Dog.

(I didn’t generate this PDF just as an answer to Lauren’s question– I’ve been planning to post it as a sample chapter for a little while now. Lauren’s question just prompted me to put it up a little earlier than planned…)


  1. #1 Lauren Uroff
    October 6, 2009

    Thanks, thanks, thanks!

    I have a practically perfect teenager – he loves SFF, he loves science, and he thinks he wants to be a biologist or maybe a rock star. And he still thinks that I can answer every science question he has based on my 30 year old college degree, subscriptions to Science News and New Science, and plain ol’ mommy abilities.

    I already have you and Emmy’s book on order at Amazon. I can’t wait until it comes!

  2. #2 Jared Grubb
    October 7, 2009

    Here’s a GREAT YouTube video that describes the double-slit experiment:

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