what's the difference between an acknowledgement and a jurat of a notary public?

Answer 1

An acknowledgment certifies three things: The signer personally appeared before the Notary on the date and in the county indicated, and the signer was positively identified by the Notary through either personal knowledge or satisfactory evidence and the signer acknowledged to the Notary that the signature was freely made for the purposes stated in the document.

The purpose of a verification with jurat is to compel truthfulness by appealing to the signer's conscience and fear of criminal penalties for perjury. The Notary certifies that the signer personally appeared before the Notary at the time of notarization on the date and in the county indicated and the Notary WATCHED the signature being made at the time of notarization and the Notary administered and oath of affirmation to the signer.

Answer 2

The notary serves as an independent witness verifying the jurat (affidavit of authenticity). The notary also usually keeps an independent record, which can be used for corroboration that the signing took place.