Tag Archives: physics

Network Oddities

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Yesterday at work I downloaded a 96MB file from a vendor web site in Texas to my workstation on the 19th floor of our building. It took about 5 minutes. Today I tried to copy it from my workstation to a server in the Data Center, in the basement. The first time I tried a windows copy. It timed out after about 20 minutes. My second try used FTP, which allowed me to monitor the progress. I killed the process after about two hours, after calculating that it would not finish until over 42 hours had elapsed. I then logged on to the server, connected to the vendor site again from there, and downloaded the file directly to the server. It took about 5 minutes this time as well. Silly cartograhical and mathematical musings

Bicycle and bus

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I rode my bicycle to and from the Rosedale park-and-ride (about three miles each way) both Monday and Tuesday. From there I took an express bus to work in downtown Minneapolis as I usually do. I gave my knees a break yesterday and drove to Rosedale, but I was back on the bike this morning. I hope to manage 3-4 carless commutes each week through the summer and early fall.

Long ago I read an article arguing that per passenger mile the bicycle was the most energy-efficient form of transportation known, not only to homo sapiens, but throughout the animal kingdom. It was in a reputable scientific publication, Physics Today IIRC, with plenty of numbers, equations, and graphs. I wonder if I could track down a copy of it.

Conservation of Energy: Not just a good idea, it is the law.

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Awareness of the problem with biofuels is spreading, but Sean Carroll speaks more to this geek than Paul Krugman or the editors of Time:

Funny thing about energy: it’s conserved! …. We bring you this reminder because a knowledge of basic physics can occasionally be helpful when formulating public policy.

In particular, biofuels (such as ethanol) and hydrogen are not actually sources of energy — given the vagaries of thermodynamics, it costs more energy to create them than we can get by actually using them, as there will inevitably be some waste heat and entropy produced.

From Energy Doesn’t Grow on Trees.

A new (for me, anyway) look at an old quote

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As long as I can remember I been aware of this famous quotation from Isaac Newton

“If I have seen further it is by standing on the shoulders of giants.”

and thought of it as a distinctly modest remark by one of the three greatest mathematicians in history.

However, there is more to it. Newton chose that image at least in part because of his feud with Robert Hooke, who was physically rather short.

From “On the Shoulders of Giants” or, Revenge is a Dish Best Eaten Cold Edition at The Inverse Square Blog, which I learned about from Cosmic Variance.