WHAT IS COOKING? Flashcards
What is cooking?
Cooking is about transferring energy. It’s about applying heat to change the structure of molecules. This encourages chemical reactions to alter flavors and textures.
Are heat and temperature the same thing?
No
What’s interesting about the physical and chemical changes that occur with heat transfer in food? Give an example using protein.
They’re usually permanent. Once a protein’s shape has been changed by adding energy to it, you can’t change it back by subsequently removing that energy; you can’t uncool a steak.
What is heat?
Heat in energy. It takes energy to evaporate moisture, make a steak brown, etc.
What is temperature?
A system of measurement that allows us to quantify how much energy is in a specific system.
The temperature of a system is dependent on what?
Total amount of energy in that body, density, and specific heat capacity.
What is density?
A measure of how many molecules re in a given space.
The denser a medium, the more _______ it will contain at a given temperature.
energy
As a rule, how do metals, liquids, and air range is density?
Metals are the most dense, liquids, then air.
Will metals at 60ºF contain more energy than liquid at the same temperature?
Yes
What is specific heat capacity?
The amount of energy it takes to raise a given amount of material to a certain temperature.
Example of SHC.
It takes exactly one calorie of energy to raise one gram of water by one degree Celsius.
Is the SHC of water higher or lower than air? What about metal?
Lower than air, higher than metal.
The same amount of energy transferred to water will raise the temperature of a gram of iron by how much more than air?
Almost ten times as much, and a gram of air by only half as much.
What is true about the SHC and the transfer of energy?
The higher the SHC of a material, the more energy it takes to raise the temperature of that material by the same number of degrees. Conversely, this means that given the same mass and temperature, water will contain about 10 times as much energy as iron and about half as much as air. Not only that, but remember that air is far less dense than water, which means that the amount of heat energy contained in a given volume of air at a given temperature will be only a small fraction of the amount of energy contained in the same volume of water. That’s the reason you’ll get a bad burn sticking your hand into a 212ºF pot of boiling water but you can stick your arm into a 212ºF oven without a second thought.
