CAN WHISTLE

Make a whistle out of an empty can. Upcycling (make something out of nothing). Help the environment and recycle your waste. This can (excuse the pun) be used when outdoors as it can be kept flat to save space and used in emergencies to get someones attention. 
What you'll need:
An empty coke can
Scissors or tin snips
Sharp 
Straight edge.

Cut the top and bottom of the can and cut the can down the middle. To get a sheet of metal that can then be cut into two strips. 

Cut one strip that is the full length of the sheet and another that is about half the length of the first. 

Bend the smaller strip around the top of the longer strip leaving enough material to cover the seam. This should make a part that can be blown through to make it whistle. After doing this bend the long strip of the metal downwards to 90 degrees to the strip you bent. Curl the metal up until it is near the top of the of the mouthpart. 

To whistle make a gap in the mouth part to blow through and hold a finger and thumb on the open sides of the whistle and hold the metal so that it curls up almost to the mouthpart but leave a gap. Now BLOW through the mouthpart and you should get the whistle to whistle if not adjust the metal part slightly and check for holes that allow the air to escape.