Remember the clock you could power with lemons?
Some of the same principles can be applied to starting a fire. You will probably never have to start a fire with a lemon but you just never know nowadays. An asteroid could strike in the middle of a lemon orchard launching millions of lemons into the air while simultaneously plunging the world in to total darkness. If you have the knowledge you too will be able to take advantage of all those lemons lying around.
The water bottle fire starter uses the old lens technique to start a fire. Remember burning ants with a magnifying glass as a kid? It's the same principle. I honestly didn't believe this would work, but sure enough, it did. Keep in mind when I tried this a few weeks ago it was over 100 degrees and I used dryer lint as tinder. Not sure how well this technique will work in a cold and wet climate.
The piston fire starter is a completely new concept to me. I'm still not certain how forcing air through a tube will cause tinder to ignite. This will make a great weekend project.
Creating fire with chemicals. I was a little hesitant to add this one to the list in fear that someone might accidentally burn their house down or cause an explosion, but It's really cool and fun. (Don't try this at home.) This technique requires the use of sugar and potassium manganate. Potassium manganate is readily available for purchase online is a very common chemical used in water treatment, fruit preservation, and as an oxidizer.
AA battery and a stick of chewing gum. My inner Macgyver comes out whenever I show people how to do this. The chewing gum wrapper is key with this technique. I have tried using only aluminum foil and other metals with very little success. The gum wrapper has a foil side and a paper side. The foil side completes the circuit allowing the paper side to ignite.
