Monday, February 22, 2021

Measuring human digestive efficiency vs. a flame

 "200 Calories" on a nutrition label doesn't describe the total flammable caloric content. I explore the differences between digestible and flammable calories using a homemade calorimeter with glass windows.

Pressure sensor: Schedule 160 pipe on McMaster: 32 ga nichrome wire: Power supply (used for ignition wire): Keithley 6.5 digit multimeter: Tek MSO 4 series oscilloscope: Soylent: Support Applied Science on Patreon:


  1. Hey ben, love your vids.

    I have a video recommendation for you, though.
    You made a video in the past about bending wood, and I think you tried to make transparent wood in a video, but I can't find it, so i might be confusing you with someone else.

    Anyway, transparent wood.

  2. Ben,
    You have a major problem with your analysis. The input and output amounts need to be included in the analysis. If the input quantity (mass) is ten times the output quantity, the efficiency of converting the food to energy would very high. In Chem Engineering we learned you need to do an energy balance that includes mass x calories/unit mass to get calories in and out. You can't assume that the mass in and mass out is the same. Some goes out as CO2, some stays in as cell growth, etc.

    1. That is right: extracting energy from food is the process by which one takes carbohydrates and essentially "slow burns" it, namely turns it into CO2 and H20, so that all the calories that the body actually used are not in the fecal matter but rather breathed out(CO2)/sweated out(H2O)/urinated(H2O).

  3. Hi Ben, do you accept direction donations?