To calculate all the breaths you take in a lifetime we have to know a couple of things. First of all we have to know the size (volume) of an average breath. Secondly we have to know how frequent we breathe (number of breaths per minute).And finally we have to decide how long you are going to live.o calculate all the breaths you take in a lifetime we have to know a couple of things. First of all we have to know the size (volume) of an average breath. Secondly we have to know how frequent we breathe (number of breaths per minute). And finally we have to decide how long you are going to live.
Step #1: Make the slingshot. 1  Make elastic bands. 2  To begin, tie 2 rubber bands together to make a long band. 3  Make a pocket. 4  Cut a small rectangle out of a scrap of leather or sturdy cloth. 5  Assemble. 6  Tie the rubber bands to the ends of a forked stick.
As the slingshot is pulled back, chemical energy is transferred from David's muscles to elastic energy in the bands of the slingshot. After the slingshot is released, the elastic energy is transferred to the stone as energy of motion (kinetic energy). You can generate maximum energy and maximum speed by using a light stone and strong bands.