Thursday, December 29, 2011

For the Love of Physics

From the End of the Rainbow to the Edge of Time - A Journey Through the Wonders of Physics

Walter Lewin with Warren Goldstein

Waltr Lewin, professor of physics at M.I.T. does spend a lot of time in this book, which describes his intro to physics lectures, talking about rainbows. He even had his young daughter hold a spraying garden hose up over her head on a cold December day in Cambridge, MA to pose for a rainbow photo.

Lewin likes to do dramatic demonstrations of the principles of physics for his M.I.T. students, swinging on a pendulum across the lecture hall or holding one, a 15.5 KG ball, up to his nose and letting it go, to show that it won't come any closer than 1/8 of an inch from that nose on it's return trip. He has so far stood still enough not to get hit in the nose with his demonstration. His enthusiasm for the subject is contagious, which is why Lewin's introductory physics class has become so popular.

Electricity, magnetism, light, Newton's laws of motion, general relativity and Maxwell's equations are all touched upon in this book of science popularization. As is customary, all this is done, even Maxwell, without taxing the reader's math skills.

Lewin's work at M.I.T. besides teaching, has been in X-ray astronomy. There is an extended section of the book covering this subject, his adventures with giant helium balloons in Australia and the reasons for studying X-rays from outer space. This work is now done with satellites, but when Lewin started either a short rocket launch for a few minutes of observation or a stratospheric balloon ride of a couple of hours were all that could be done. X-rays are absorbed by Earth's atmosphere or we would all be fried.

M.I.T. has kindly put the whole series of Lewin's lectures, in video, on the web. You can watch to your heart's content at MIT Open Courseware.

By the way, Professor Lewin wants you to know the degree of uncertainty in all of your measurements. If you don't know that, you don't know anything!

Saturday, December 3, 2011

THe Filter Bubble

What the Internet Is Hiding From You

Eli Pariser

Social scientists have been telling us for a decade or more that we tend to associate with people that are just like ourselves, watching either Fox or MSNBC but not both, even moving to cities where more people share our own political and/or religious views. Eli Pariser proposes that the algorithms written into Google, Facebook and other social networks and search sites have been written to reflect ourselves like a mirror.

This results in the ghettoization of society. One person's Facebook feed is filled with vegetarian, Buddhist and Occupy Wall Street posts. Another's has Sean Hannity, climate change denial and right to life posts. In the next cubicle the screen is filled with Ron Paul, Iggy Pop and the latest home fusion technology schemes. My Google search on the same keywords will not give me the same results as yours. Google is trying to give each of us what we want, according to the history of our internet use, as stored in "cookies" deep within our own hard drives.

The companies which run these sites are storing up detaied profiles of each of us, in order to feed us advertising for the things we, individually, are most likely to buy. Their approach is much more sophisticated than the coupons that supermarkets print for us at checkout time, trying to woo us away from the dog food we just bought with an offer of 25 cents off on a can of the competing brand. According to Pariser, they know all about or personal, work, recreational and political lives and stand ready to sell that information to any bidder. Perhaps this is why my Gmail spam folder always has an ad for recipes for Hawaii's favorite tinned meat product.

Pariser contends that these algorithms serve to accelerate the breakup of civil society. All we see on the internet is the same as we see on our favorite cable channel, hear from our friends and hold strongly in our hearts. We must be right, because everyone we know agrees with us.

The solution? I know it can be painful, but I suggest that you go ahead and "like" Michael Moore's Facebook page and Rush Limbaugh's. Search for the latest news from Pope Benedict and from Vladimir Putin. Watch those Fox News clips and a few from Al Jazeera. Cognitive dissonance is a good thing.