Hello, Internet. Well, here we are, 500,000 subscribers.

Well, actually, by the time I finished this video, it's a bit more than that, but who knew after I promised to do a Q&A that the Pope would resign?

Anyway, when I uploaded my first explanation video just over two years ago now, I would never have expected this.

More than half a million subscribers and 16 videos with more than a million views? Who knew rapidly spoken

educational videos could be so popular? Thank you, Internet. Now as promised, though

slightly behind schedule, it's time to answer some of your questions. What's your

educational background? I went to school in New York where I earned two college

degrees, one in physics and one in sociology. After that I moved to London and earned a

PGC in science education and became qualified as a physics teacher in England.

How long does it take to create a video?

I've tracked my time to get an accurate answer and every minute of final video you see takes me between 10 and 20 hours of writing and animating to make.

So a typical 5 minute video represents 50 to 100 hours of work.

While that's a lot, it doesn't include the research phase, which is difficult to quantify.

Some of the videos I've made I've been collecting notes on for more than a year before starting.

What was your favorite video to make? The 2012 video was the most fun by far, mainly because I didn't have to do a lot of complicated research and I got to complain about things that I don't like. What change would you make to the education system? Instead of grouping kids by age, I try grouping them by ability instead. The idea that just

because a kid is 14 years old, they're ready for trigonometry is weird. No other part of

human society organizes itself this way, and for good reason, it artificially slows down the

best and the brightest. What do you think should be in the curriculum but isn't? Computer programming. I was kind of shocked and horrified when I started teaching in the UK to discover that there

were no real computer programming lessons.

Of course, there are only so many classes in a day and everybody wants their pet subject

taught in school, so the equally important question is what to get rid of to make room for

computer programming, and without the slightest hesitation, I ditch the foreign language

...