Answer:
Specifically, Realism was a French artistic movement that rejected the drama and emotionalism of the previous Romantic movement in favour of the typical, the real and the contemporary. The subject matter changed from the theatrical, composed figure paintings of historical or classical themes, to observations of the lives of ordinary people...Millet's "The Gleaners" or the work of Daumier.
The choice of subject matter followed through into the work of the Impressionists, and if you look at the work of Corot, you can see how there was also a degree of technical inspiration too.
It's worth noting that the term "Realism" has also been used as the counterpoint, or antithesis, more recently to abstract art. Strictly speaking that is wrong.
Impressionism is a little harder to define, as it was a new way of looking at the world and representing it in paint.
The previous, acedemic, style was to clearly define seperate forms...figures, buildings, trees...with contour and tone: outline and the difference in light values on the scale white-grey-black.
The Impressionist approach a scene from a slightly different angle....forget what you know to be there, what do you see in terms of the light hitting the scene you are looking at...instead of applying black to darken areas of shadow, what do you actually see there ?
What is the light doing...what colours do you SEE ?
Its worth pointing out that the new invention of putting oil paint in tubes allowed the artist to get out into the world, rather than make sketches and paint the scene later in the studio from memory. It gave them the freedom to capture the nuances of light with an immediacy that hadn't been possible before.
The results were full of light, dazzlingly so, and in capturing the fleeting effect of light on the subject, after the initial "shock of the new" had passed, they were seen to possess a truer more vital sense of reality. The paint on the canvas was fragmented, stoccatto brush-strokes of purer color, that seemed to recreate the vibrancy of the scene.
It's important to point out that the Impressionists had no interest in any form of expressionism, simply capturing the moment was enough, without using it as vehicle for expressing emotion...that would come later. It was said of Monet : "He is just an eye...but, my God, what an eye !"
So the essential difference between the two, is that the focus of Realism is on the subject matter..on WHAT is painted, whereas Impressionism was more concerned with looking at the world and HOW to paint it.
Step-by-step explanation: