Starting a fire with multiple choices increases your chances of survival, especially in camping or hiking areas. Apart from using water with light bulbs, a plastic bag (or sandwich bag) can also be used to make fire especially when you are on a mountain.
Other necessary materials include wood, rocks and twigs. The wood and rock are ground until they look like dust. The darker and finer they are, the easier they are to absorb heat and cause fire. The twigs are used to rekindle the flame obtained during the process. Dead grass is also required for spreading the fire.
Fill the empty sandwich bag with water from the stream or your urine. The sandwich bag acts as a magnifying glass with water in it and attracts sunlight to cause heat on the powdered wood and rocks.