martha asked in Science & MathematicsMathematics · 4 months ago

# What is different between calories and joules?

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• Zirp
Lv 7
4 months ago

Calorie is defined as the amount of energy needed to heat up a gram of water one degree celsius

Joule is defined as amount of energy needed to speed up a gram by one meter per second,  or as watt times second

Ultimately it's very much like comparing a liter to a gallon

• 4 months ago

1 Joule = 1 Newton * 1 meter.

Joules measure the amount of work that is done to move a mass through a space.  If you move a 1 kg object on the Earth's surface (or more accurately, it's accelerating downward at an acceleration of g) a distance of 1 meter, then you'll use 1 Joule of energy to do so.

1 Calorie is the amount of heat energy it takes to raise the temperature of 1 gram of water by 1 degree Celsius.

4.186 Joules = 1 Calorie

They both measure energy, which is why they convert easily, but the way they are defined is slightly different.

• ?
Lv 7
4 months ago

note that food calories are actually 1000x these calories.

1 cal = energy needed to raise the temperature of 1 gram of water by 1° centigrade.

• 4 months ago

joules are the standard SI (metric) unit of energy

calories are an obsolete unit of energy, from the old cgs system

1 joule is equal to:

0.2390 cal (gram calories)

2.390×10^−4 kcal (food calories)