Electricity and water are never a good thing to mix, but you never want to be caught out in the dark without a flashlight. Whether you're just a hiker and worried about rain, or prefer to canoe or kayak and are constantly worried about ending up in the drink, a waterproof flashlight is just as cheap and easy to make, as it is to buy.
Disclaimer: Water and electricity are a bad combination. It can short out your equipment, and depending on what it is it can give you a decent jolt. While I have made and tested this flashlight take everything said with a grain of salt and some common sense. Always be careful when putting dangerous elements together.
Step 1: What you need
A few things to consider. Stay away from self sealing tires. They are lined with a slime that is forced into punctures where it will harden. Needless to say, that would become a horrific mess if you try to cut it. If you don't have any tubes with holes in them you could always consider upgrading and then having the old inner tubes to play with, and if you do have a tube with a hole then you of course want to use a section that isn't pierced for this project.
Inner tube from a bicycle
needle and thread
clear plastic bag
Utility knife or scissors