Who do you think is the greatest scientist of all time and why?

Newton or EInstein.

Newton essentially founded mechanics (Newtons 3 Laws) and the basic law of Gravity. He helped formulate early calculus and applied it brilliantly to physics. He also made contributions in optics

Einstein in addition to the well-known theory of Relativity (Special & General), was essentially the person who "discovered" the photon. You can also say he first proved the existence of molecules. He also made fundamental contributions to quantum mechanics (the part dealing with Bosons) & first suggested lasers.

I would say that is a toss up between Charles Darwin and Albert Einstein. These two scientists, more than anyone, had changed the way people thought.

Before Darwin, it was assumed that life existed either by design or by chance. Darwin discovered a mechanism by which life could have come to be by order of gradual changes in progeny. He called this mechanism "natural selection." After Darwin, there was a profound new understanding of the natural world.

Einstein's discovery revolutionized our understanding of the physical world without making any observations. Unlike Darwin, Einstein did not carefully observe and interpret the natural world to make his discovery. Einstein, instead, made his discovery purely on the theoretical basis. Einstein realized that Newtonian physics did not apply to all frames of reference. His theory of relativity gave us an understanding that everything we know depends on our frame of reference. His theory showed us that space and time are not separate from each other, but instead are interconnected and depend on one another.

These two discoveries filled great holes in understanding and have allowed later scientists to think in a better way.

It may be an unanswerable question. There were many great scientist. To imply one was the greatest would imply some kind of measure for great. Maslow (the psychologist) would get my vote as the greatest or most significant for mankind because he studied happy people and qualified their behavior. No one came before him and unfortunately no one has followed him. His work has yet to be quantified.

In physics using most significant as a measure:

Newton (he developed the mathematics in additon to laws of motion, gravity, laws of optics ...)

Einstein (relativity, photoelectric effect, statistical physics, Brownian motion ....)

Maxwell (unification of electricity and magnitizum)

Carnot (thermdynamic theory discovering the perfect engine which has not been made todate)

The list is long.

here is a list of possibilities.

euler

newton

gauss

maxwell

Boltzmann

bardeen

hilbert

dirac

schrodinger

feynman

fermi

bose

einstein

the list goes on. each person either developed or helped develop fields of mathematics or physics that have become so important to science and engineering that we wouldnt have much of what we have without them. they are all inseperable however. a good example is bardeen. without the IC, we wouldnt have had many of the advances in physics because we would not have been able to solve complex problems well. but without quantum mechanics (einstein, bose, feynman, shrodinger, dirac, etc), much of the electrical engineering world would be hidden from us.

I think that Einstein is the greatest scientist because of his discoveries in atomic physics and special and general relativity.

Me! Jk.