When do we use a silent 'h'?

Name: The School of the Air @ABCEducation
Uploaded: 2020-03-20T01:29:31-0400
Duration: 8 min 17 s
Description: Australian students who live in remote areas attend school remotely through The School of the Air. This film excerpt from 1958 shows how they used radio to communicate with their teacher and their classmates, to learn and have fun.