All you will need for this is some 1/2 inch pvc pipe ( 1/2 inch diameter of hole in the middle)

Step 1: the Materials!

All you need is-
-a saw
-some string
-1/2 pvc pipe

Step 2: How Long Should Your Bow Be?

Your bow should be the as long as your arm span.

Step 3: Where the String Goes

On the ends of the pipe you can cut a V shape cut 2 inches from each end.

Step 4: Now for the Length of the String. and Tying

The length of the string should be 4 inches shorter than the bow. For the tying string you should make a loop knot and put the string through the loop.

Step 5: Final Step!

Now bend the pipe so you can loop the other end of the string on the the other V shape cut. The bow should be fairly bend like the picture below

Step 6: And Your Done!

And all you have to do is get a straight stick or buy a wooden dowel, sharpen then fire

Note the bow is a weaker than other wood bows but is still strong.