On 28 February 2014 13:38, Russell Standish <[email protected]> wrote:
> On Fri, Feb 28, 2014 at 12:47:05PM +1300, LizR wrote: > > On 28 February 2014 07:47, John Clark <[email protected]> wrote: > > > > > > > > Food energy is not all that dilute, a 1000 calorie jelly doughnut has > > > about as much chemical energy as a hand grenade. > > > > > > You have 1000 calorie jelly doughnuts??? (What's that in metric units?) > > > > Actually, a calorie _is_ a metric unit (it is defined as the amount of > heat needed to raise 1 gramme of water by 1 degree Celsius (or > Kelvin)), but it is not an SI unit. > > Actually, there are two different definitions of "calorie", a small > calorie (as defined above) and a large calorie (equivalent to 1000 > small calories) which is commonly used in dieter's books. > I remain confused. How many grammes of water can a jelly doughnut heat through 1 degree? And does it really have the same energy as a hand grenade? (This could make food fights more, er, interesting...) > > To convert from calorie to SI units, you need to use the specific heat > of water, which is about 4200 J/kg, meaning that 1 cal is about 4.2 > Joules, or 1 Cal is about 4.2 kJ. > > What do they teach in schools these days? > The above, actually, as I happen to know from helping my son with his physics homework. Except they never mentioned calories (or kCal) just joules. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
