Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Explosive & Food Calories

  1. Mar 11, 2004 #1


    User Avatar

    A http://muller.lbl.gov/teaching/Physics10/chapters/1-Explosions.htm [Broken] listed what I have posted below. Does it make sense to compare the calories of a chocolate chip cookie to the calories of TNT? Maybe there is more calories in TNT than 1 but not all of it can be released fast enough to be apart of the explosion. Or maybe people don't digest all the calories in a cookie and so the calories listed are smaller than how much it actually contains.

    Code (Text):

    object                                Calories in one gram

    gasoline                              10
    chocolate chip cookies                5
    bullet (moving at speed of sound)     0.01
    methane gas (CH4)                     13
    battery (flashlight)                  0.01
    battery (computer)                    0.1
    hydrogen gas (H2) for fuel cell       26
    TNT or dynamite, by convention*       1
    real TNT (trinitrotoluene)            0.651
    modern High Explosive (PETN)          1.06
    meteor (at 30 km/sec)                 100
    Last edited by a moderator: May 1, 2017
  2. jcsd
  3. Mar 11, 2004 #2


    User Avatar
    Science Advisor

    First off, kilocalorie would seem more correct for a physics text, but food-calorie makes sense to a layperson.

    Second, it explains the difference between power and energy as its rational. Its not the total energy, rather how quickly the energy is delivered.

    In demolition, it seems much talk is spent on how fast things happen, seems to follow here.

  4. Mar 11, 2004 #3
    We commonly measure energy in calories, so it does "make sense" to compare different sources of energy with calories. As to whether or not it makes sense to compare cookies to dynamite; remember, it is an election year. -Mike
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook