Saturday, July 05, 2008

This and That

  • It's summer in the city again - last week saw the first really hot days in Frankfurt. One of the many nice things about Frankfurt is that it's easy to escape to the countryside - the meadows and fields at the foot of the Taunus hills for example are a great place for a after-work walk,



    with the city skyline in the background...



    Both photos have actually been taken from the same place, at around the same time. If you look closely, you can see the shadow of one of the towers projected onto another building, a phenomenon one can witness in Frankfurt at sunset around the summer solstice.

    My time in Frankfurt is coming to an end soon, and preparations for the move and all the things involved are one of the main reasons for my sparse blogging activity lately.


  • The week also saw the record average price for gasoline so far, with €1.60 per litre, or $9.40 per gallon, which makes commuting to Heidelberg quite expensive. I'm quite happy that my old Twingo is content with a bit more than 5 litres per 100 km, or, eh, has a mileage of about 45 miles per gallon.

    I've always found the concept of mileage a bit confusing, not just because of the conversion to strange units such as miles and gallons, but also because of the reciprocal involved. Fortunately, there are now online tools to ease the conversion, and even Google does the job.

    It seems that the use of "miles per gallon" can mislead when searching for fuel efficiency - that's because the differences of inverse quantities are not very intuitive. You can check this out for yourself with an (a bit silly...) interactive quiz. But I'm still surprised that this deep insight has made it onto the pages of Science.


  • Speaking of Science, this week's edition of the magazine is a Special Issue with reports on results from the first MESSENGER flyby at Mercury last January (subscription required, unfortunately). Which reminds me that I owe someone a longer post about the flyby I should publish soon.


Have a nice weekend!

5 comments:

Jake said...

Never really given much thought to visiting Frankfurt, however the meadows and fields may just be what I need right now

Phil Warnell said...

Hi Stefan,

“I'm quite happy that my old Twingo is content with a bit more than 5 litres per 100 km, or, eh, has a mileage of about 45 miles per gallon.”

First off, what the heck is a “Twingo”?

“I've always found the concept of mileage a bit confusing, not just because of the conversion to strange units such as miles and gallons, but also because of the reciprocal involved.”

Yes I have the same problem only in this case its trying to understand the metric viewpoint despite the fact that Canada has been metric for more then 30 years. Also I never understood why it’s expressed in how many litres per 100 kilometers instead of simply how many kilometers per litre. This for me is counterintuitive.

“Which reminds me that I owe someone a longer post about the flyby I should publish soon.”

I don’t know who that is, yet I will tell you I’m looking forward to such a post.

Best,

Phil

stefan said...

Hi Phil,

a Twingo is just a car ;-)

Interesting that the litre/100 km are counterintuitive to you. It seems to depends on where you grow up. Anyway, I guess it's indeed harder to estimate gasoline savings in km/litre units?

Cheers, Stefan

Plato said...

Do a search function over on the right side and type in "Shadows."

You'll come up with a "New Kind of Calendar" that should have been linked too as well Stefan. Long Island.

Phil might have liked the comparisons drawn in the comment section as well?

This is an "ancient idea" that was part of the secrets I learnt about The Giza Plateau:)

Umm, Ya, ye know, Plato an all:)

Phil Warnell said...

Hi Stefan,

“a Twingo is just a car ;-)”

Just a car that gives you 20 kilometers to the litre! There are very few cars available in Canada that will give that kind of economy and still seat four; unless you want to part with big bucks on a hybrid which I feel is a stupid technology anyway. I did have a Renault several years ago and although a fun car to drive found it not too good in the reliability department. I think they should spend the money to develop the ultimate electric car with a super capacitor storage system rather then batteries; something that can be charged as fast or faster then pumping gas. Electric if developed properly just has so much potential it should be the only thing supported with huge R&D grants and incentives.

As for the different ways of stating fuel economy no matter which way you slice it is a reciprocal rather then a linear relationship with the limit as one over infinity. They play similar games when quoting resistance to heat transfer in building construction materials when they quote things in R Value which is the (approximate) reciprocal value of U value. To calculate heat loss you would never use R yet only U. From a marketing standpoint it’s advantageous however to show something becoming greater and greater, yet the real difference is becoming less significant much more rapidly. Perhaps similar to U value it should be expressed as litres/kilometers which for the Twingo would be .05 with the Hummer at about .20 and the limit being .00 or perpetual motion :-)

Best,

Phil