Wow!

[personality]

"You can see just how efficient the human body is if you compare your body to a car. A typical car in the United States gets between 15 and 30 miles per gallon of gasoline (6 to 12 km/L). A gallon of gas contains about 31,000 calories. That means that if a human being could drink gasoline instead of eating hamburgers to take in calories, a human

Comments

[zanfur]

That's actually a lot of bunk, unless you're looking at nothing at distance covered.

Human + bike = 200lbs, for a relatively fit human who would be biking 1000 miles. Human + car = 2600lbs, for a car that gets 30mpg (that is, a light one, like a Saturn SL1 -- cars that get 15mpg are more like 5000 lbs, making the difference moot). Taking a look at the work done, those 31000 calories moved 2600lbs 30 miles, versus 200 lbs 1000 miles. The ratio of work done in an hour (i.e. efficiency) isn't anywhere close to 3:100 (30:1000), it's more like 75:100.

Human is still more efficient, on a bicycle. It's nowhere near as drastic as those statistics would seem to indicate.

Taking a 200lb human who runs 330mpg (= 26m/.3L * 3.8L/1g), the efficiency ratio is in the favor of the car, at around 75:66 (actually closer to 78:66).

Human is less efficient, unaided.

Okay, now lets compare

[zanfur]

how much energy it takes to get a gallon of gas vs. a 'gallon' of grain. Oil has to be pumped up and refined, though the grain does require a tractor to harvest it... I still feel like this is Apples to oranges :)

Tony

Ah, but perhaps...

[personality]

Well, why do we ask this question? Sure, the car moves itself and therefore does a lot more work, but why must the car be moved? Perhaps humans aren't more efficient, but they are more efficient at moving just themselves.

If you could build a 200lb car that got 300mpg, I'd drive it.