Pressure Cookers Cook Hotter and Quicker – The Ideal Gas Law

Chemistry, Food
[caption id="attachment_22958" align="alignright" width="480"] Modern 8.5 quart steel pressure cooker[/caption] Your time is limited. Besides, you are concerned about tenderness and nutrition. So you are in the market for a pressure cooker. But you are just a bit curious about how and why they work. And you are not certain which one to buy. Meats and Vegetables Water ordinarily boils at 212° Fahrenheit (100° Celsius). So food cooked in an open saucepan,1 whether by boiling or steaming, cooks at approximately that temperature. Using a Pressure Cooker In an open saucepan, water boils at atmospheric pressure, something over 14 pounds per square inch. However, when water boils in a pressure cooker, steam pressure is considerably higher. Now steam is essentially gaseous water. This brings to mind our high-school days and the…
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Why Balloons Blow Up Round

[caption id="attachment_13619" align="alignright" width="440"] Balloons.[/caption] When you blow up latex balloons and build up some pressure in them, unless they are especially made to become some other shape, they tends toward roundness—they assume a spherical shape. Balloons blow up round! Why does it do that? Let’s look at the simple math and physics of the thing. Stretching Requires Force Take an ordinary piece of burst balloon and pull on it with your fingers. It takes a definite force to accomplish that, doesn’t it? And the task becomes more difficult the more you stretch it. We call the exertion “force.” It takes force to stretch the rubber. Since the required force becomes greater the more you stretch the skin of balloons, it is clear the more air you blow into them,…
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