Your car broke down in the middle of nowhere and you really need to make a fire to provide warmth and help rescuers find you faster. You have no matches, and have never learned the fine art of rubbing two sticks together to make fire. You remember that your kids were burning holes in newspaper with a magnifying glass, and then you realize that your glasses might work in the same way. Here's how.
Gather tinder. Look for material that is fine and dry, including any paper, lint or cotton. Look in your pockets or rub the lint off the bottom of your socks. If you can't find anything else, you can use your own hair. Find smaller twigs and branches to fuel the fire once it is going and place them in a pile.
Make a small tinder nest about the size of your palm, and then take off your glasses and place your glasses a few inches above the tinder nest until you focus the sunlight into a very small dot or beam. The smaller the beam, the hotter the light.
Keep the beam very still to allow the light to create a burning ember of the dried tinder. This may take a bit of time so be patient. As it begins to burn, gently blow on it with even breathes until it flames up.
Place additional tinder and small twigs on the flaming nest to continue to build the flame.
- This method is not going to work at night!