This INSET could last between 1/2 hour to 1 hour. It is also something you could apply in class to teach pupils how to ask good quality questions. My other hat is a performance coach, which specialises in questioning skills, and a Neuro Linguistic Programming Master practitioner, which also relies on open, clean questions to avoid influencing the answer. The power of asking the right question accelerates learning and development, whilst the problem with asking the wrong question can create barriers and close the pupil down. I wish I had learnt this technique at the beginning of my career.