This is an extremely easy whistle very loud!!! you will need an empty zip fizz container poor similar cylinder and your lungs. Warning if you do not rinse out the zip fizz container you will get a cloud of dust in your face. This whistle make a very loud and shrill noise it doesn't sound very good to me but it will definitely get someones attention!
Step 1: Open the Container
open the empty zipfizz container.
Step 2: Whistle
blow really hard into the top of the container holding out parallel to your face. blow down.