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Workshop 3

2. Conversion of Energy Units

cashews

Cashews have the energy content of about 5.6 Calories/gram. (You can find this number in a food Calorie table where the energy available for various items is tabulated. Later in these workshops you will see how the energy values are obtained in the laboratory.)

In the video, Chuck has about 47 grams of cashews for a total of about 263 Calories. Each food Calorie (remember that 1 Calorie = 1000 calories), is equivalent to 4184 Joules, so the cashews have a total of about 1,100,000 Joules (1.1 MJ).

How did we calculate this?

(47 grams) (5.6 Calories/gram) (1000 calorie/Calorie) (4.184 joules/calorie) = 1.1 MJ

Using similar calculations, we find that the energy content of 47 grams of cashews is equivalent to the energy of about: 1 kg of TNT, 1 cubic foot of natural gas, 1.1 ounce of gasoline, 72 AA batteries, or a typical candy bar.

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