Here is a video that shows 90 seconds that could save your life. How to actually MAKE A FIRE with a lens, rather than just burning a hole in a leaf. (Or frying ants, which seems to be the other thing that kids like to do with magnifying glasses.)
By forming your target material into an efficient ball, you will be able to start a fire even with very small lenses. Like less than an inch across small. The finer the individual fibres, and the more densely they are packed, the more effective is your ball of smigtin (smouldering iginition tinder).
Want to master Microsoft Excel and take your work-from-home job prospects to the next level? Jump-start your career with our Premium A-to-Z Microsoft Excel Training Bundle from the new Gadget Hacks Shop and get lifetime access to more than 40 hours of Basic to Advanced instruction on functions, formula, tools, and more.