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.
Report Abuse. Check the expiry date! If it doesn't have an expiry date, I'd say it's probably good for at least a few weeks. If it's getting old, check it for mold before you use it; most mold that grows on sour cream would be quite visible if there was enough of it. Meklar Â· 9 years ago. Thumbs up.