How do you reach the whistle notes like mariah carey?

i know it can be done. i've heard that it has something to do with air pressure/flow across the top of your vocal cords with them barely open. i've heard other things, too, but im confused.

i meant like techniques to practice with. i don't want to strain my voice. i know she does it a certain way.

You must be able to do it WITHOUT STRAIN. The way I do it is finding a space in my head cavity where those notes resonate, form the space in my throat and just sing. I don't have a specific technique. It comes from practice and natural ability.

all it is is practise

Practice very very very hard

she probably uses her head voice to get those "whistle" notes. try that.

You have to be a soprano to hit all those really high notes. Like a really high Soprano 1. Like me. It's not easy. You gotta know to drop your jaw and open the space in your throat.