Gif 2Focus of a Hyperbola
Gif 3How to Make a Hyperbola
Gif 4Parabola as Locus
Gif 5Parabola as Construction
The larger the $ |a|$ is, the more the graphs narrows.
The larger the $ |a|$ is, the more narrow the parabola is. Or, another way to think of it, the closer that the value of $a$ gets to zero, the wider the parabola becomes.