Caltech has posted an extensive set of physics lectures from Richard Feynman. Best of all, they’re free.

Dr. Evelyn Lamb, writing for Scientific American:

On Monday, the Onion reported that the “Nation’s math teachers introduce 27 new trig functions.” It’s a funny read. The gamsin, negtan, and cosvnx from the Onion article are fictional, but the piece has a kernel of truth: there are 10 secret trig functions you’ve never heard of, and they have delightful names like “haversine” and “exsecant.”

I have actually used haversine in some mapping code written while in grad school. The others were new to me.

(via: Scholar and gentleman, Brian Bridges)

James Clear, Lifehacker:

Learning how to say no is one of the most useful skills you can develop, especially when it comes to living a more productive and healthy life. Saying no to unnecessary commitments can give you the time you need to recover and rejuvenate. Saying no to daily distractions can give you the space you need to focus on what is important to you. And saying no to temptation can help you stay on track and achieve your health goals.

Clear goes on to discuss recent research that shows the powerful difference between “I can’t” and “I don’t” when deciding to say no.

John Gruber:

Yes, it’s plastic, but there’s nothing cheap about it. It has a far better fit and finish, and feels way better in your hand, than Apple’s previous foray into plastic iPhones, the 3G and 3GS. The 5C feels like a premium product.

This move is about establishing the iPhone as a two-sibling family, like how the MacBooks have both the Airs and the Pros. Think of the 5C as the Air, and the 5S as the Pro. Or iMac and Mac Pro. The iPhone is growing up as a product family.

Everyone got it wrong. The 5C wasn’t about releasing a super cheap iPhone, it was about releasing a superb phone for the middle of the iPhone lineup. Apple has never chased the low end of any market. In hindsight, it seems foolish that everyone (myself included) thought Apple would break from tradition.

Federico Viticci, MacStories:

At a keynote held today in Cupertino, Apple’s Senior Vice President of Worldwide Marketing Phil Schiller officially introduced the iPhone 5s, the successor to last year’s iPhone 5 and the major new entry in the iPhone line-up. Schiller referred to it as the “most forward-thinking phone anyone has ever made”.

As widely expected, the iPhone 5s has the same industrial design of the iPhone 5, with an anodized aluminum back and diamond cut chamfered edges and glass inlays, 4-inch Retina display, and Lightning connector. However, the iPhone 5s comes with a visible change in the Home button: through a brand new system called Touch ID, a sensor available under the Home button will allow iOS to recognize a user’s fingerprint for authorization and security purposes.’

Cody Fink, MacStories:

During today’s media event at the Apple Campus in Cupertino, California, Apple’s senior vice president of Worldwide Marketing, Phil Schiller, took the stage to announce the iPhone 5c. The iPhone 5c is Apple’s first plastic-bodied phone with a 4-inch screen, is shaped like the iPod touch, and is also Apple’s first iPhone that’s available in an array of bright colors. The 16 GB iPhone 5c starts at $99 on contract.

The New York Times has a really cool interactive page that shows the connections between film directors and their stars:

A long-running relationship between an actor and a director can indicate an artistic understanding, a functional routine or even a marketing strategy. Here, a selection of notable directors are shown with actors they cast in at least four films.

Adrienne Crezo, Mental Floss:

In 1978, a very nervous 23-year-old Steve Jobs (sporting some magnificent facial hair) was interviewed on KGO-TV San Francisco. Though footage of the interview itself has (probably) been lost, the prep from 30 minutes before still exists. This is billed as Steve’s first TV appearance, and it certainly seems that’s true.

Even geniuses get nervous.

Stu Woo, writing for The Wall Street Journal:

Fans live for long points. But exactly how much action is there in a tennis match? We took a stopwatch and timed two matches at the U.S. Open last week to find out. The answer: Not as much as you’d probably think. In the two matches we studied, only 17.5% of the time was spent actually playing tennis.

Baseball and football are played at an even lower percentage.

Jacob O’Neal with a really cool animated infographic:

Did you know that your car will take in 20,000 cubic feet of oxygen to burn 20 gallons of fuel? That’s the equivalent of a 2,500 sq. ft. house!

If your only experience with a car engine’s inner workings is “How much is that going to cost to fix?” this graphic is for you! Car engines are astoundingly awesome mechanical wonders. It’s time you learned more about the magic under the hood!