Cooking is the human process or skill of preparing food for eating by combining, mixing, and heating various ingredients. Methods of heating vary widely depending on the dish being prepared, cultural customs, the skill set of the cook, and available resources, with techniques ranging from baking, to boiling, to frying, to roasting, to smoking, and so on. This process of heating food for consumption is unique to humans, and has been deeply influenced by the cross-cultural exchanging of ingredients throughout history. Cooking is usually done in a kitchen with the aid of appliances, and may be done out of pure necessity, for recreational purposes, or even professionally in restaurants.
Simmering something when cooking is bringing a liquid to a state of being just below boiling. If the contents begin to boil, the heat should be turned down to return the liquid to a light bubbling. Simmering makes the difference in the finished product of fluffy or burnt rice.
Yield is how much finished product that you will have. It also refers to the amount of product after being processed (peeled, cooked, butchered, etc.). Professional recipes should always state a yield.
To dispose of cooking oil, first allow the oil to cool completely and pour it into a sealed non-recyclable container, and throw it away in the garbage. The old oil can also be frozen until hardened, then thrown away once it comes out of the container in one piece. It can also be mixed with an absorbent material, such as cat litter or sawdust, before being thrown away.