The sound of a scale is determined by the particular pattern of intervals that constitutes it. Major and minor scales are the most common scale types in many styles of music, but there are many others.

Major scales contain seven notes (before the scale starts again an octave higher) and consist of a particular structure of semitones (two adjacent notes) and tones (notes that are separated by two semitones).

This specific distribution of tones and semitones is what defines any major scale, regardless of the starting note:
You can use the buttons that indicate the root to shift (or transpose) the scale to a different root note. Note that the distribution of tones and semitones (illustrated by the dots on the piano keys) never changes.

(Note: People unfamiliar with a piano keyboard may be confused by the fact that adjacent notes are not necessarily different colored keys. For example, the distance between E (E) and F (F) and also if (B) and C (C) is a semitone, even if they are two white notes):
Here we will look at the intervals spanned between these notes. We will start by analyzing the interval between C and D: from C sharp, there is a semitone, and from C sharp to D, there is another semitone. Two semitones make up a whole tone.

In this way it is possible to analyze the entire major scale:

do, re, mi, fa, sol, la, si, do
tone, tone, semitone (between E and F), tone, tone, tone and semitone (between B and C).
Or what is the same:

T T S T T T S (where T: pitch; and S: semitone) .1
As seen below:

Intervals on the C major scale.