is that brittle is inflexible, liable to break or snap easily under stress or pressure while flexible is capable of being flexed or bent without breaking; able to be turned, bowed, or twisted, without breaking; pliable; not stiff or brittle.s that brittle is (uncountable) a confection of caramelized sugar and nuts while flexible is (chiefly|engineering|and|manufacturing) something that is flexible. As adjectives the difference between brittle and flexible. As nouns the difference between brittle and flexible.
If you decrease the temperature of a fixed amount of gas at constant pressure, the combined gas law reduces to Charles's law. In this case, volume will also decrease. If you were to maintain a constant volume while decreasing the temperature, the pressure would also have to decrease in order to satisfy Gay-Lussac's law.
This is why the speed of sound (which has a direct relation with temperature) decreases with altitude. About pressure variation with altitude:- The pressure of air is nothing but the weight of air column over a given surface. Suppose we are standing near the surface of earth.