Why the larger the value of | a | in quadratic function, the smaller the opening

Why the larger the value of | a | in quadratic function, the smaller the opening

When x is a certain value, for example, in the function y = AX2
X = 2, when the value of a is equal to plus or minus 2, y is equal to plus or minus 8, which is smaller than plus or minus 3 when x = 2 in rectangular coordinate system. According to the above reasons, we can draw a parabola, the larger the value of | a | is, the smaller the opening is