I am new in Tridion and want to know what is the difference between a Metadata Schema and a simple Schema?
Basically main difference is that Simple schema is to define the properties of component where as metadata schema is also similar to simple schema but if you use metadata schema then this kind of component is get stored in broker so that you can use these component for querying the data from broker that why we are using this schema with publication , folder , structure group , page etc
To elaborate on Saurabh's answer and including Albert's blog mentioned, a SDL Tridion Schema (aka. Component Schema or Normal Schema) is used to define both the content and metadata fields for a certain type of content, which is used to create Components. It is an XML Schema, and thus describes the XML which will be allowed inside the Component.
As mentioned, a Component can have in its Schema a definition for both Metadata and Content fields. So the Schema for a Component can be seen as a normal Schema and a Metadata Schema in one.
Besides Components, there are also other items in SDL Tridion, like Organizational items (Folder, Structure Group, Publication, etc.) and things like Component- and Page Templates. These items do not have a user definable Schema like a Component does. But SDL Tridion does allow you to add (user assignable) Metadata to these items. For that you have the Metadata Schema.
A Metadata Schema is there to define (metadata) fields for items other than a Component. As such is is an extract of an XML Schema, only defining the Metadata (fields).
So simply said, a Schema is for Components and a Metadata Schema is for all other items.
In the Content Manager, Components are based on the type called "Schema". Schema is simply a definition of the Component.
Metadata Schema is used to add metadata values to Publications, Folders, Virtual Folders, Structure Groups, and Pages.