Urban legend
says that in a single trip of 100 miles or so your car will burn more oxygen
than your body will burn in a life-time.

With a few simplifications, and your factor-label skills we should be able to
prove or disprove this idea.

If you are interested, keep reading.

**STUFF YOU WILL NEED**

1.** **Mr K's truck 15 mi/gal
mileage

2. Round trip distance to Pyramid
Lake and back (gotta go fishing once in while) 116 miles.

3. Gasoline has an average
composition of C_{8}H_{18} (isooctane).

4. Assume complete combustion
(products are CO_{2} and H_{2}O).

5. Air is 21% O_{2}

6. Assume atmospheric pressure is 650
mm Hg. Assume it is a mild winter day 10 C. for a temperature.

7. An adult breath is about 500 cm^{3}
of air

8. The average number of breaths is
15 breaths per minute.

9. Human lungs are about 13%
efficient. We return about 87 % of the O_{2} we breathe unchanged.

**General approach:** figure out how much O2 the truck needs for the round
trip. Find out how long it would take an adult to breathe that much O2.

Let me know how far you get.

If you are interested, e-mail or hand Mr. K your worksheet for up to **100 points of extra credit.**