A screw thread, often shortened to thread, is a helical structure used to convert between rotational and linear movement or force. A screw thread is a ridge wrapped around a cylinder or cone in the form of a helix, with the former being called a straight thread and the latter called a tapered thread. A screw thread is the essential feature of the screw as a simple machine and also as a fastener. The mechanical advantage of a screw thread depends on its lead, which is the linear distance the screw travels in one revolution.
Sour cream is a dairy product with a short shelf life. Typically it is good for 2 to 3 weeks from when purchased. Always check the expiration date on the container.
By Alison Soltau. Sour cream products commonly have a âbest by,â or âsell byâ date. A âbest byâ date refers to the last date on which the unopened, refrigerated product is guaranteed to still be at peak quality. In the case of sour cream, that means it has, up to that point, retained its fresh flavor, texture, aroma, and nutritional values. This date is about quality, not safety.