When playing the drums you may come across a term called the open high hat and what that refers to is when you strike the high hat your foot is coming off the pedal and separating the two high hat cymbals to create an open sound.
Now normally what you're going to do is you're going to strike the high hat when the two high hat cymbals are in the position of being half open or kind of slightly closed and then you're going to pull your foot off the pedal which creates an open sound and then finally depress this pedal which ends up cutting off the sound. So I'm going to do this slowly so you can see how this works and then I'll play it in time so you can see how it sounds like in a pattern.
Slowly open high hat sounds something like this. What you'd be doing is hitting the edge of high hat cymbals as its opening up creates that opening sound and then you close it. Now if you’re going to do it in a pattern it works in conjunction with other notes that would sound something like this. And that's a common pattern you'd hear in the style of rock. Now something you'd hear more in Jazz would sound something like this.