There some beginners who confuse the bass A just below middle C with the treble E just above middle C, and the bass B just below middle C with the treble D just above middle C.
For some beginners they do not view the middle C ledger line as an another line and that it is the line between the two staves. Possibly some think that the two staves do not flow from one to the next. And, there can be misunderstandings when writing a note such as treble D in the bass clef. There are some beginners who do not understand how the two staves are interrelated. I have seen some examples from teachers where the middle C line is extended, usually in another colour, so the beginner can understand how the middle C ledger line works.
Associated with this confusion of the notes above and below middle C, there can be other aspects of learning that will require explanation and reinforcement. The beginner needs to understand that although music is written vertically, the piano keys are horizontal; this adjustment has to be made.
Also, all beginners must learn their musical alphabet forwards and backwards, in seconds and thirds, thoroughly. This can be later be applied to the reading of the notes using the language of line and space notes.
In addition to this, another confusion is the fact that middle C is written in both the bass and treble clefs. It doesn’t help that the bass Middle C is written close to the bass stave and that the treble Middle C is written nearer the treble clef.
Teaching aids such as a grand stave on a magnetic board where the beginning learner can move the notes into position themselves, is extremely helpful. As is always the case, referring to the piano is crucial. Worksheets are useful for reinforcing the concept, once introduced and covered. This worksheet contains my own clipart however the New Zealand bird clipart is by Grubby Graphics. Their logo is at the bottom of the page.
I have made up a set of cards where the beginning pupil needs to identify the notes that move from one clef to another. Both hands must be used, as some beginning pupils find it a little difficult to understand how the hands are opposite and that only the position of the number 3 finger is constant between the two hands.