How are slow motion and fast motion formed in movies? What does this mean?

When the shooting speed exceeds 24 frames per second, it is usually called slow motion and is displayed at normal speed.

Slow motion has an effect that normal speed shooting can't achieve by prolonging the film and television time of the subject and combining the enlarged time with the narrative foreshadowing.

If you have an iphone5s or above, you can feel it intuitively.

Or you can rely on some apps, such as instagram, musical.ly, Mamma Mia, second shot and other video shooting applications, and also have the effect of slow-motion snapshot.