Interviews at schools are often led by vice principals, principals, or other school administrators. These people haven’t studied HR, they specialize in other fields, and they often struggle to compare the interview answers of job applicants, unless there’s a skilled HR professional sitting in the hiring committee.
What is more, most job applicants have the same education and experience (or none experience), and they struggle to choose the best person for the job based on scientific criteria. At schools, the decisions are often emotional, not rational. They may prioritize the candidate who shows similar opinions, and have similar hobbies as they do have.
Look around, find something you have in common
Look around the office. You may find some pictures, or other things, that indicate hobbies, interests and opinions of your interviewers. You can sometimes deduct these things from the discussion in the interview.
Try to find something you have in common, and elaborate on it in your answer. Mutual hobbies, interests, opinions–all of that will help you to build good atmosphere in an interview, and good atmosphere will strengthen your chances of getting the job.
And if you like to play musical instruments, or enjoy going to the nature, or doing sports, you should definitely mention the hobbies in your answer. They show the range of activities you can do with the children.