How bike gears work ?

I have been using Bike in States for some time . Though my bike is not really high end it comes with gears and I was not well aquainted with the working of gears. So I had to ask google and here is what it gives me back .

These two links really explains it in lay man's words

http://bicycleuniverse.info/eqp/gears.html

http://auto.howstuffworks.com/gears1.htm

Hope you find it helpful to understand also.

Let's not reinvent the wheel !!

One of the main reason I really love open source and free software that it allows user to reuse existing solution to any given problem. This allows them who have solved that problem to improve their solution and also for others who just want to use it to solve other problems and move on. We have enough problems to solve. Similarly as Janine Benyus attarcts our attention towards billions of years of wisdom and perfected solution. One of the best talk on TED I have come across ..

She explains how billions of species which were on earth much before we even came into existence have faced many similar issues and have found the solution which are natural,perfec and kind of cost effective. While we are relatively new on earth , the path we have chosen is not really in sync with natures and which is very different from what other organisms have achieved. Our solutions further damages natural equilibrium and eventually will be reason for our own destruction. And also it takes considerable effort to find out new solutions . Instead we can just ask the nature !! All we need to do is find similar problem in nature and understand the solution developed by other organisms and just adopt same solution .. We are done... Move on to find new problem.. new organism and new solution and show will go on.

Ok nice idea but we do not really have a nice catalog about such ideas,organisms,solutions and in which fields directly related to us we can use it. Well Janine Benyus has thought about exactly same problem and came up with asknature website which tries to address exact same issue. Its a nice attempt though not much comprehensive yet but it will eventually become one and I sincerely hope it becomes a perfect source for such information.

Looking at the vast amount of knowledge available in the form of these other living creatures , we have so much to learn .. I feel like we are not even in KG then .. Lets get started !!

Physics For Future Presidents

Physics For Future Presidents Is a course of physics at University Of Berkeley which is taught by one of the experts 

Dr. Richard Muller. I have been going through some of the web casts of his lectures and they are very very good.Must

see if you have slightest interest in Physics.

SkyCar

Today i listened to Paul Moller a person who does not seem to have thought of anything else other than skycar all his life :). In ted video he explains what he has been doing in this field. Some of the points he explains :

*In USA we are not building new highways but transportation is going to increase by at least 30 % in next decade. How are we going to cope up with it ?

* Why not use something like skycar for long distance traveling(60 miles +). We already use airplanes .. so skycar should not be crazy idea to go after. Henry Ford hinted something similar in 1940.

* There are other interesting use cases of this vehicle one of which is rescue.

* The technology involved is complex but certainly lot simpler than what we are using to go and be on moon and mars.

I think this is an interesting idea. Also we could achive something which can easily fly at different heights it will very useful to avoid traffic. As in air we can fly at different heights , all can be at same point. Also we do not need to build roads. Also renewable energy research is making great progress these years. It it could reach to a point to power our skycars of future , indeed sky will only be the limit. In poor countries also good infrastructure can be rapidly built as it eliminates requirement of road which is one of the biggest problem at such places. Connecting to remote places etc become so much easier.
May be while we think of this different ideas might come forward which will be entirely different but this thing does have potential to change something fundamentally and put as in completely new era.

String Theory

When as a child i read a book आकाशाशी जडले नाते (meaning got connected with sky) and got very much interested in astrophysics, cosmology . After that i took computer science as career option but sometimes i love to visit my older interest and read some stuff about it.
Today i watched a very interesting ted video about String theory . Brian Greene is one of the great physicist of our time and he is also prolific speaker who can simplify something like string theory which you and i can understand at least conceptually. He takes us on path about how these theories came into existence . Newton explained much about gravity but he could not explain certain things like how and why it is there. Einstein attempted to solve the question by trying to come with Unified theory. He added 4th dimension as time along with three dimensional space around us. Then came Kaluza who tried to explain the question raised by Einstein's theory by adding one more dimension in space. He tried to add one dimension and see what he gets and after solving the equations he got famous electromagnetic equation so he was very thrilled that he found unified theory. The speaker tries to explain how string theory is related to this .
We all know everything is made up of molecules which are made up of atoms which in turn can be divided into electrons ,protons & neutrons . This can be further divided into quarks. String theory takes this theory one step further and explains how this can be thought of divided into strings vibrating in different dimensions causing everything to be the way it is in this universe. But the problem with String theory is it can be applied practically if we consider only 3-4 dimensions of space. If only we think of 10 spatial and one time dimension string theory can be practically to understand the Universe. And that might suggest there are more dimensions out there.
If they are there why can not we see it ? Simply because the dimension might be very very small that we can not see it which is possible as we are not always able to see things which have already proven to be there. How can we 'look' for such dimensions then ? Brian Greene tells us that in coming years (may be 5-6 ) we might be able to come up with experiments which might detect (or prove it does not exist) other dimension in space. One of the experiments can be large hadron collider. They are trying to collide particles travelling around speed of light and the hope is that when they collide some mass might get converted into energy and escape into other dimensions. We can measure this by the loss of mass + energy. This might prove the existence of other dimensions.
The speaker also tries to explain that more or less in 20 very important physics constant we can explain many things in universe. But we do not know why these constant have those values that they have but one thing is certain Universe as we see it today will not be same if those constants had different value. And so its likely that other dimensions are there and we are not able to 'see' them .
Frankly speaking anything more than 3 dimensional in space starts becoming complex to me , so i am not going to go in much details of String theory but just to have general idea of what are those basic questions for Unified theory and how scientists are trying to come up with theories to explain Universe, everybody should watch this video.

Apan kay shikalo .. Mhanje ?

I completed my schooling from Maharashtra India in Marathi medium school. In science text book at the end of each chapter we had apan kay shikalo (What did we learn ? ) section which would summarize chapter contents and also answer some tricky things/questions raised in the earlier part of chapter. It was really interesting read (most of the times we would find we did not understand many things from chapter). I like to read and i do come across interesting ideas while reading randome stuff on internet. I plan to write about these things after i have read about it. Mainly summarizing and listing people behind those for future reference as well as for improving my own understanding of things i am reading about. Hope to fill this particular blog with lots of interesting ideas.