A paper cracker is like firecrackers - it makes a loud noise (not as loud as firecrackers :p). The difference? You can make one with only a piece of paper!
Step 1: Materials
All you will need is:
-A sheet of lined paper
Yes, you heard me right. Only a sheet of paper. But for best sound (loud), then go with paper that's thinner than blank paper, since it needs to unfold really easily. Kind of like Magazine Paper.