An Invitation to History of Science: A short introductory course for undergraduates

in first class we came to know that main principle of science is all event(physical) has physical cause.this boundary condition should always be remembered in doing any branch of science

YES I THINK ALSO THAT IT IS CORRECT BECAUSE WHATEVER WE DO THERE IS ALWAYS A PHYSICAL CAUSE BEHIND ANY PHYSICAL EVENTS.
FOR EX. MESSAGE IS SENT FROM ONE PART OF BODY TO ANOTHER,THIS THIG HAPPENS DUE TO NEUROTRANSMITTER THAT ARE CHEMICALS THAT ALLOW THE MESSAGE TRANSFER.WITHOUT THEM NO MESSAGE TRANSFER CAN TAKE PLACE.

Well if you consider subjects like "psychology" as scientific studies , then this thing may not hold true .
And , what about the supernatural events like some tribes in Africa who know how to fly (actually they demonstrated this long time back)
Can the physical event boundary explain these things ....

what is theory?
In my view theory is a something that can explain the natural phenomena ,with some assumption.
please answer this question.
Is general theory of relativity and quantum mechanics inconsistance with each other?
("A Briefer history of time ")

AS PER ME THEORY HAS SOME CONSOLIDATED PROOF THAT PROVIDES A PROPER EXPLANATION TO SOME PHENOMENA BASED ON CERTAIN EVIDENCES (AND ON ASSUMPTIONS)
I DON'T KNOW ANYTHING ABOUT THEORY OF RELATIVITY AND QUANTUM MECHANICS(AND I THINK NEITHER YOU ALSO DON'T KNOW ANYTHING ABOUT IT).BOTH THE SUBJECTS GIVE INFORMATION ABOUT 2 DIFFERENT THINGS.FOR EX.QUANTUM TUNNELING I THINK HAS NO RELATION WITH EACH OTHER.QUANTUM THEORY GENERALLY ABOUT THE SMALL PARTICLES WHILE RELATIVITY IS ABOUT THE PARTICLES THAT ARE MOVING WITH SPEED COMPARABLE TO LIGHT.SO I THINK TILL NOW THERE IS NO RELATION BETWEEN BOTH.

i dont know about relativity an quantum mechanics but i think that quantum mechanics deals with small particals and heisenburgs uncertainity theory comes into play according to which both position an velocity of an object cannot be determined simultaniously .so quantum mechanics talks about chances (probability) of occuring of event but relativity predicts about occurence of event. eg if i throw a stone on u with all parameters like gravity,viscosity,angle,velocity,distance known i can predict correctly whether it will hit u r not(according to relativity )but i can only say about chances of hitting u according to quantum mechanics.making a theory which satisfies both this is todays challenge

in the first lecture we discussed the point that (every physical event has a underlying physical cause).....now suppose there is a book kept on a table and i am not feeling like to see it there then i will remove it,here what i think the main physical cause is our mental cause....the idea which i want to convey is that the above sentence can be said in more appropriate way just in rhe form of newton's first law(a body persists its state of rest or of uniform motion unless acted upon by an external unbalanced force)........

but where did the feeling of removing the book came from.it came from our mind and stimulus in our mind(to remove the book)arouse due the chemicals present.

Well we are not controlled by chemicals , we control some (like giving signal to our hand to move) , and some control us (like blinking of our eyes) . there is some kind of mutual grey are between the chemical processes and our stimuli , which I think even science cannot explain ....

I AM NOT REFERING THAT WE ARE CONTROLLED BY CHEMICALS.BUT THEN ALSO THERE ARE SOME CHEMICALS PRESENT THAT HAVE SOME CORELATION WITH OUR THINKING(LIKE GIVING SIGNAL-WELL THERE IS A CHEMICAL RESPONSIBLE FOR EVEN SIGNAL TRANSFER TAKING IN NEURONS )WELL IF THERE NO INVOLVMENT OF THE CHEMICALS THEN WHY DOES ONE GET DISEASE LIKE ALZIMER,BRAIN TUMOR.ETC. IF THE DEFICIENCY OF THESE THINGS ARE OCUURING.
WELL THE PROTEINS PRESENT IN OUR BODY THAT ARE COLLECTION OF AMINO ACIDS THAT CONTROL MANY THING IN OUR BODY.

well what u mean by we.(we) chemical control other chemical so we chemical think we r not chemical.well a person drinks ten glasses of rum do u think he acts normal.the 'we' which controls chemical cannot control it ,without chemical interaction.so 'we'r entirely dependent on physical object.so v r physical i do agree that science have made little progress in understanding human behavior but it does not mean it cannot

on the second lecture the three philosphers about which we came to know were thales,anaximender and anaximenes....among these three the idea of anaximenes was most appealing to me......if we think considering one self to be a person of that time then we can convince ourselve that air shold be the basic mareial and all the other things can be thought as the same material air but at different degree of density...(this idea is most scientific among the ideas given by the other philospher till anaximenes)
COMMENT
IT MUST BE HARD TO DIGEST AT THAT TIME THAT HOW FIRE CAN BE FORMED BY AIR...............

Well you see , at that time also , if people could think of a property like density it was fabulous .
But you see , they couldn't explain that why can't we beat or destroy solid things and make air .

Interpretation is the integral part of SCIENCE.
All science whatever we know is because of interpretation.At the time of christopher columbus where people think that earth was flat ,this was also the result of interpretation.then Aristotle came out with new idea that earth is a sphere .He also thought that earth is stationary and sun ,moon and other planets move around earth this is another result of interpretation , although it is not true but it pave the path for further development in this area.Copernicus objected this and said that all heavenly bodies need not to revolve around earth indeed they all of them revolve around SUN.hence we see that all science whatever has been discovered is just the result of interpretation.
Today also we are just trying to interpret "THE MISTRY OF DARK ENERGY" .

in this lecture sir asked us 2 make the other three components out of the 4 from any one given. as an example we took water n made earth, gas n fire out of it ,by decreasing the interatomic distances of the particles. i am till confused as to how can we create fire from water?

Was the phenomena of light and sound deeply discussed by the greek scholars? How did they attach thesephenomena to their respective world view?

1.In the Earth's rotating frame of reference, a freely moving body follows an apparent path that deviates from the one it would follow in a fixed frame of reference.
2.In Foucault's Pendulum, the plane of oscillation appears to rotate at a rate depending on latitude because of the rotation of the Earth.
3.The repetition of the motion of Stars, The Sun, The Moon and the Planets during the day and the night provided evidences for earth's rotation during ancient times.

Evidences for the spinning of the Earth -

* Foucault Pendulum Experiment - The Foucault experiment was first conducted in 1851,by the Frenchman Léon Foucault.He suspended a heavy iron ball from a 200 ft (61 m) wire,creating a pendulum,from the dome of the Pantheon in Paris.He put sand underneath the pendulum,and placed a pin on the bottom of the ball,so it would leave a mark on its swing from side to side.On each swing,over the course of 24 hours,the mark in the sand would move to the right.The direction in the path showed movement of the earth against the swing of the pendulum.

* A more modern proof of the rotation is shown by the orbits of artificial satellites.A satellite is launched from the Kennedy Space Center at a 30 degree angle to an orbit 100 mi (161 km) above Earth.Its orbit stays at approximately the same plane in space.If Earth did not rotate,the satellite would pass over Cape Canaveral each time it completed an orbit,but it does not.As it completes the first orbit,it flies over Alabama and over Louisiana on the third.Each time the satellite passes over locations in the United States,it is 1,000 mi (1,609 km) farther to the west.Tracking stations have made this observation with hundreds of satellites.

* Another way of proving rotation is through the prevailing winds.In the northern hemisphere,they move in a counter clockwise direction,while in the southern hemisphere,they blow clockwise.

* The result of the Coriolis Effect is that the projectiles are deflected towards the right at northern latitudes and towards the left at southern latitudes.




    

Evidences for the spinning of earth:-
1.The Coriolis Effect:-
In the Earth's rotating frame of reference, a freely moving body follows an apparent path that deviates from the one it would follow in a fixed frame of reference. Because of this Coriolis effect, falling bodies veer eastward from the vertical plumb line below their point of release, and projectiles veer right in the northern hemisphere (and left in the southern) from the direction in which they are shot. The Coriolis effect has many other manifestations, especially in meteorology, where it is responsible for the differing rotation direction of cyclones in the northern and southern hemispheres. Hooke, following a 1679 suggestion from Newton, tried unsuccessfully to verify the predicted half millimeter eastward deviation of a body dropped from a height of 8.2 meters, but definitive results were only obtained later, in the late 18th and early 19th century, by Giovanni Battista Guglielmini in Bologna, Friedrich Benzenberg in Hamburg and Ferdinand Reich in Freiberg, using taller towers and carefully released weights.
2.Foucault Pendulum:-
The most celebrated test of Earth's rotation is the Foucault pendulum first built by physicist Léon Foucault in 1851, which consisted of an iron sphere suspended 67m from the top of the Panthéon in Paris. Because of the earth's rotation under the swinging pendulum the pendulum's plane of oscillation appears to rotate at a rate depending on latitude. At the latitude of Paris the predicted and observed shift was about 11 degrees clockwise per hour. Foucault pendulums now swing in museums around the world.
3.Day and Night phenomenon.

Evidence of Earth's rotation

In the Earth's rotating frame of reference, a freely moving body follows an apparent path that deviates from the one it would follow in a fixed frame of reference. Because of this Coriolis effect, falling bodies veer eastward from the vertical plumb line below their point of release, and projectiles veer right in the northern hemisphere (and left in the southern) from the direction in which they are shot. The Coriolis effect has many other manifestations, especially in meteorology, where it is responsible for the differing rotation direction of cyclones in the northern and southern hemispheres. Hooke, following a 1679 suggestion from Newton, tried unsuccessfully to verify the predicted half millimeter eastward deviation of a body dropped from a height of 8.2 meters, but definitive results were only obtained later, in the late 18th and early 19th century, by Giovanni Battista Guglielmini in Bologna, Friedrich Benzenberg in Hamburg and Ferdinand Reich in Freiberg, using taller towers and carefully released weights.

Foucault pendulum experiment as an evidence:
The best evidence in my opinion of Earth's rotation is the Foucault pendulum experiment by physicist Foucault in 1851, which consisted of an iron sphere suspended 67m from the top of some church in Paris. Because of the earth's rotation under the swinging pendulum the pendulum's plane of oscillation appears to rotate at a rate depending on latitude. At the latitude of Paris the predicted and observed shift was about 11 degrees clockwise per hour. Now a daysFoucault pendulum is common in allmost all museums of the world or in scientific centres.In TIFR there is one of this kind.in these modern pendulums one can observe a change in less time.
-actually this is a great experiment from which we can make a person understand that earth rotates.

Now a days there are some more evidences which we can give as launching of a sattelite.
Rising and setting of stars and planets in the night sky at different places occurs in different manner.