---recommended to use in full screen--- you can scroll up and down on your track pad or scroll wheel on an external mouse and it will detect it. look inside to see how it works and in the notes and credits section. this project can tell the difference between the up and down arrows from the scroll wheel.
I recently found a project that used a when up arrow pressed hat block and decided to test it out when testing i found that scratch will not recognize the scroll wheel in a Boolean block but will when using a hat block, of course if you are using this you wouldn't want the same effect to happen when someone presses the up arrow or down arrow, so i used a if not key pressed block which allows the scrolling to be detecting since it's not recognized in the Boolean block. Also it has come to my attention that I am not the first person to do this and there are projects dating back to 2008 of people showing off this same method I am not trying to say that I created this method but I also came up with it while testing feel free to use this code also spread this project around so other scratchers can learn of this method. this is just a quick tech demo I made while looking on scratch :p